Garrett AS, Maddock RJ.
NeuroImage, in press
fMRI was used to dissociate neural responses temporally associated with the subjective experience of emotion from those associated with the perception of emotion-inducing stimuli in order to better define the emotion-related functions of the amygdala, lateral orbital frontal cortex (OFC), and hippocampus. Subjects viewed aversive pictures followed by an extended post-stimulus period of sustained subjective emotion. Brain regions showing activation paralleling the period of sustained subjective emotion were distinguished from those showing activation limited to the period of aversive picture presentation. Behavioral results showed that subjective ratings of emotion remained elevated for 20 s after offset of the aversive pictures. fMRI results showed that viewing aversive pictures activated the amygdala, lateral OFC, and hippocampus. Subjective emotion (present both during and after aversive pictures) was temporally associated with activation in the right lateral OFC and left hippocampus but not the amygdala. Ratings of subjective emotion were correlated with activation in the right lateral OFC and left hippocampus. The results support direct amygdala involvement in emotion perception but suggest that amygdala activation is not temporally associated with subjective emotion that occurs after the offset of emotion-related stimuli. The results are consistent with a general role for the lateral OFC in monitoring or reflecting on internal experience and show that hippocampal activation is sustained during a period of subjective emotion, possibly related to enhanced memory encoding for the aversive pictures.
Friday, August 18, 2006
ARTICLE UPDATE - How do emotion and gaze direction interfere with overt orienting of visual attention?
Bonifacci P, Ricciardelli P, Lugli L, Chitti F, Nicoletti R.
Cognitive Proceedings, 7 (supp 5), 155
BACKGROUND: Several studies using spatial cueing paradigms have demonstrated that observing gaze direction may trigger a reflexive visual orienting in the direction of the other person's gaze. Recently, it has been reported that facial expression may enhance the reflexive orienting of attention to gaze stimuli. However, some researchers have also suggested that, rather than facilitating attentional orienting away from the face, emotional expressions may, in fact, delay or prevent orienting. In the present study we investigated the effects of facial expression and gaze direction on a visual orienting oculomotor task to test whether an angry face may or may not interfere with visual orienting. METHOD: Participants performed an oculomotor task in which they had to make a saccade towards one of two lateral targets, depending upon the colour of the fixation dot which appeared at the centre of the computer screen. The instruction dot remained visible for 50 ms and then disappeared. At different time intervals (stimulus onset asynchronies, SOAs: 50, 100, 150 ms) following the onset of the instruction cue, a real face (gazing either to the right or to the left) was presented at the centre of the monitor. Gaze direction could be congruent or incongruent with respect to the instruction and target location. Facial expression was also manipulated. In half of the trials the diverted gaze (i.e., congruent or incongruent) appeared with an angry expression, whereas in the other half the face had a neutral expression. Participants were instructed to saccade either to the target on the left or to the target on the right (the targets were visible throughout the trial), as indicated by the instruction dot, while completely disregarding the face because it was irrelevant for the task. RESULTS: Eye movement recordings on correct trials showed that saccades congruent with the direction of the distracting gaze had shorter latencies than incongruent ones. However, the time-course of this effect varied depending on the facial expression. With a neutral expression, the congruency effect was found only at the shortest SOA (50 ms). On the contrary, for the angry face the congruency effect occurred at the longer SOAs. These findings suggest that gaze direction (even when task-irrelevant) is capable of interfering with the orienting of visual attention, and that faces with an angry expression may hold attention and affect its orienting longer than a neutral expression.
Cognitive Proceedings, 7 (supp 5), 155
BACKGROUND: Several studies using spatial cueing paradigms have demonstrated that observing gaze direction may trigger a reflexive visual orienting in the direction of the other person's gaze. Recently, it has been reported that facial expression may enhance the reflexive orienting of attention to gaze stimuli. However, some researchers have also suggested that, rather than facilitating attentional orienting away from the face, emotional expressions may, in fact, delay or prevent orienting. In the present study we investigated the effects of facial expression and gaze direction on a visual orienting oculomotor task to test whether an angry face may or may not interfere with visual orienting. METHOD: Participants performed an oculomotor task in which they had to make a saccade towards one of two lateral targets, depending upon the colour of the fixation dot which appeared at the centre of the computer screen. The instruction dot remained visible for 50 ms and then disappeared. At different time intervals (stimulus onset asynchronies, SOAs: 50, 100, 150 ms) following the onset of the instruction cue, a real face (gazing either to the right or to the left) was presented at the centre of the monitor. Gaze direction could be congruent or incongruent with respect to the instruction and target location. Facial expression was also manipulated. In half of the trials the diverted gaze (i.e., congruent or incongruent) appeared with an angry expression, whereas in the other half the face had a neutral expression. Participants were instructed to saccade either to the target on the left or to the target on the right (the targets were visible throughout the trial), as indicated by the instruction dot, while completely disregarding the face because it was irrelevant for the task. RESULTS: Eye movement recordings on correct trials showed that saccades congruent with the direction of the distracting gaze had shorter latencies than incongruent ones. However, the time-course of this effect varied depending on the facial expression. With a neutral expression, the congruency effect was found only at the shortest SOA (50 ms). On the contrary, for the angry face the congruency effect occurred at the longer SOAs. These findings suggest that gaze direction (even when task-irrelevant) is capable of interfering with the orienting of visual attention, and that faces with an angry expression may hold attention and affect its orienting longer than a neutral expression.
Wednesday, August 16, 2006
ARTICLE UPDATE - Attentional capture by task-irrelevant fearful faces is revealed by the N2pc component
Martin Eimer and Monika Kissa
Biological Psychology, in press
We measured the N2pc component as an electrophysiological indicator of attentional selection to investigate whether fearful faces can attract attention even when they are entirely task-irrelevant and attention is focused on another demanding visual monitoring task. Participants had to detect infrequent luminance changes of the fixation cross, while ignoring stimulus arrays containing a face singleton (a fearful face among neutral faces, or neutral face among fearful faces) to the left or right of fixation. On trials without a target luminance change, an N2pc was elicited by fearful faces presented next to fixation, irrespective of whether they were singletons or not, demonstrating that irrelevant fearful faces can bias the spatial distribution of attention. The N2pc to fearful faces was attenuated when face arrays were presented simultaneously with a target luminance change, suggesting that concurrent target processing reduces attentional capture by emotional salient events.
Biological Psychology, in press
We measured the N2pc component as an electrophysiological indicator of attentional selection to investigate whether fearful faces can attract attention even when they are entirely task-irrelevant and attention is focused on another demanding visual monitoring task. Participants had to detect infrequent luminance changes of the fixation cross, while ignoring stimulus arrays containing a face singleton (a fearful face among neutral faces, or neutral face among fearful faces) to the left or right of fixation. On trials without a target luminance change, an N2pc was elicited by fearful faces presented next to fixation, irrespective of whether they were singletons or not, demonstrating that irrelevant fearful faces can bias the spatial distribution of attention. The N2pc to fearful faces was attenuated when face arrays were presented simultaneously with a target luminance change, suggesting that concurrent target processing reduces attentional capture by emotional salient events.
Friday, August 11, 2006
ARTICLE UPDATE - Neuroimaging Studies of Emotional Responses in PTSD.
Liberzon I, Martis B.
Annuals of the New York Academy of Sciences, 1071, 87-109
Neuroimaging research offers a powerful and noninvasive means to understand healthy as well as dysregulated emotional processing in healthy subjects and PTSD patients. Functional neuroimaging findings suggest specific roles for subregions of the medial prefrontal (mPFC), orbito frontal (OFC), anterior cingulate (ACC), and insular cortices as well as the sublenticular extended amygdala (SLEA) and hippocampus in various components of emotional processing. Some of the same regions appear to be associated with emotional response to trauma, and with symptom formation in PTSD. Neuroimaging findings of emotional processing in healthy subjects and PTSD patients are discussed, addressing the specific roles of cortical regions like mPFC, ACC, and insula, and their potential contribution to PTSD pathophysiology. Processes of cognitive-emotional interactions and social emotions are discussed in an attempt to synthesize the prefrontal findings in healthy subjects and PTSD patients. Further links between functional neuroanatomy of emotional responses and neuroendocrine stress regulation are proposed.
Annuals of the New York Academy of Sciences, 1071, 87-109
Neuroimaging research offers a powerful and noninvasive means to understand healthy as well as dysregulated emotional processing in healthy subjects and PTSD patients. Functional neuroimaging findings suggest specific roles for subregions of the medial prefrontal (mPFC), orbito frontal (OFC), anterior cingulate (ACC), and insular cortices as well as the sublenticular extended amygdala (SLEA) and hippocampus in various components of emotional processing. Some of the same regions appear to be associated with emotional response to trauma, and with symptom formation in PTSD. Neuroimaging findings of emotional processing in healthy subjects and PTSD patients are discussed, addressing the specific roles of cortical regions like mPFC, ACC, and insula, and their potential contribution to PTSD pathophysiology. Processes of cognitive-emotional interactions and social emotions are discussed in an attempt to synthesize the prefrontal findings in healthy subjects and PTSD patients. Further links between functional neuroanatomy of emotional responses and neuroendocrine stress regulation are proposed.
ARTICLE UPDATE - Right hemispheric dominance in processing of unconscious negative emotion.
Sato W, Aoki S.
Brain and Cognition, in press
Right hemispheric dominance in unconscious emotional processing has been suggested, but remains controversial. This issue was investigated using the subliminal affective priming paradigm combined with unilateral visual presentation in 40 normal subjects. In either left or right visual fields, angry facial expressions, happy facial expressions, or plain gray images were briefly presented as negative, positive, and control primes, followed by a mosaic mask. Then nonsense target ideographs were presented, and the subjects evaluated their partiality toward the targets. When the stimuli were presented in the left, but not the right, visual fields, the negative primes reduced the subjects' liking for the targets, relative to the case of the positive or control primes. These results provided behavioral evidence supporting the hypothesis that the right hemisphere is dominant for unconscious negative emotional processing.
Brain and Cognition, in press
Right hemispheric dominance in unconscious emotional processing has been suggested, but remains controversial. This issue was investigated using the subliminal affective priming paradigm combined with unilateral visual presentation in 40 normal subjects. In either left or right visual fields, angry facial expressions, happy facial expressions, or plain gray images were briefly presented as negative, positive, and control primes, followed by a mosaic mask. Then nonsense target ideographs were presented, and the subjects evaluated their partiality toward the targets. When the stimuli were presented in the left, but not the right, visual fields, the negative primes reduced the subjects' liking for the targets, relative to the case of the positive or control primes. These results provided behavioral evidence supporting the hypothesis that the right hemisphere is dominant for unconscious negative emotional processing.
Friday, July 21, 2006
ARTICLE UPDATE - Neural substrates associated with evaluative processing during co-activation of positivity and negativity: A PET investigation.
Jung YC, An SK, Seok JH, Kim JS, Oh SJ, Moon DH, Kim JJ.
Biological Psychology, in press,
Affective symmetries, such as the positivity offset and negativity bias, have been postulated to be attributable to distinct activation functions of the positive and negative affect systems. We investigated the neural substrates that are engaged when the positive and negative affect systems undergo parallel and integrative processing. Eleven subjects were scanned using H(2)(15)O PET during choosing the subjective feeling produced by a stimulation pair of pictures or words. Four different conditions were designed for contrast: pure positivity, pure negativity, positivity offset, and negativity bias. The dorsolateral prefrontal activation was associated with positivity offset and negativity bias condition, whereas the ventromedial prefrontal activation, together with limbic and subcortical activations, was associated with pure positivity and pure negativity condition. The results indicated that positivity offset and negativity bias are not merely due to asymmetric activations of the positive and negative systems, but integrative processing of higher neocortical levels is involved.
Biological Psychology, in press,
Affective symmetries, such as the positivity offset and negativity bias, have been postulated to be attributable to distinct activation functions of the positive and negative affect systems. We investigated the neural substrates that are engaged when the positive and negative affect systems undergo parallel and integrative processing. Eleven subjects were scanned using H(2)(15)O PET during choosing the subjective feeling produced by a stimulation pair of pictures or words. Four different conditions were designed for contrast: pure positivity, pure negativity, positivity offset, and negativity bias. The dorsolateral prefrontal activation was associated with positivity offset and negativity bias condition, whereas the ventromedial prefrontal activation, together with limbic and subcortical activations, was associated with pure positivity and pure negativity condition. The results indicated that positivity offset and negativity bias are not merely due to asymmetric activations of the positive and negative systems, but integrative processing of higher neocortical levels is involved.
ARTICLE UPDATE - Anticipation of affective image modulates visual evoked magnetic fields (VEF).
Onoda K, Okamoto Y, Shishida K, Hashizume A, Ueda K, Kinoshita A, Yamashita H, Yamawaki S.
Experimental Brain Research, in press
We investigated the interaction between anticipation of positive and negative affective images and visual evoked magnetic fields (VEF). Participants (n = 13) were presented emotionally positive or negative images under different anticipatory conditions, and their subsequent brain responses were recorded by magnetoencephalography (MEG). In the Affective Cue conditions, the cue stimulus indicated the emotional valence of the image, which followed 2 s later. In the Null Cue conditions, the cue stimulus did not include any information about the valence of the image. In the No Cue conditions, the affective image was suddenly presented, without a cue stimulus. The VEF amplitude for the negative image in the Affective Cue condition was smaller than that of the positive image in the Affective Cue condition and that of the negative image in the Null Cue condition. This result suggests that anticipation of the valence of affective images modulates the processes of the visual cortex.
Experimental Brain Research, in press
We investigated the interaction between anticipation of positive and negative affective images and visual evoked magnetic fields (VEF). Participants (n = 13) were presented emotionally positive or negative images under different anticipatory conditions, and their subsequent brain responses were recorded by magnetoencephalography (MEG). In the Affective Cue conditions, the cue stimulus indicated the emotional valence of the image, which followed 2 s later. In the Null Cue conditions, the cue stimulus did not include any information about the valence of the image. In the No Cue conditions, the affective image was suddenly presented, without a cue stimulus. The VEF amplitude for the negative image in the Affective Cue condition was smaller than that of the positive image in the Affective Cue condition and that of the negative image in the Null Cue condition. This result suggests that anticipation of the valence of affective images modulates the processes of the visual cortex.
ARTICLE UPDATE - The locus ceruleus is involved in the successful retrieval of emotional memories in humans.
Sterpenich V, D'Argembeau A, Desseilles M, Balteau E, Albouy G, Vandewalle G, Degueldre C, Luxen A, Collette F, Maquet P.
Journal of Neuroscience, 26, 7416-7423.
Emotional memories are better remembered than neutral ones. The amygdala is involved in this enhancement not only by modulating the hippocampal activity, but possibly also by modulating central arousal. Using functional magnetic resonance imaging, we analyzed the retrieval of neutral faces encoded in emotional or neutral contexts. The pupillary size measured during encoding was used as a modulator of brain responses during retrieval. The interaction between emotion and memory showed significant responses in a set of areas, including the amygdala and parahippocampal gyrus. These areas responded significantly more for correctly remembered faces encoded in an emotional, compared with neutral, context. The same interaction conducted on responses modulated by the pupillary size revealed an area of the dorsal tegmentum of the ponto-mesencephalic region, consistent with the locus ceruleus. Moreover, a psychophysiological interaction showed that amygdalar responses were more tightly related to those of the locus ceruleus when remembering faces that had been encoded in an emotional, rather than neutral, context. These findings suggest that the restoration of a central arousal similar to encoding takes part in the successful retrieval of neutral events learned in an emotional context.
Journal of Neuroscience, 26, 7416-7423.
Emotional memories are better remembered than neutral ones. The amygdala is involved in this enhancement not only by modulating the hippocampal activity, but possibly also by modulating central arousal. Using functional magnetic resonance imaging, we analyzed the retrieval of neutral faces encoded in emotional or neutral contexts. The pupillary size measured during encoding was used as a modulator of brain responses during retrieval. The interaction between emotion and memory showed significant responses in a set of areas, including the amygdala and parahippocampal gyrus. These areas responded significantly more for correctly remembered faces encoded in an emotional, compared with neutral, context. The same interaction conducted on responses modulated by the pupillary size revealed an area of the dorsal tegmentum of the ponto-mesencephalic region, consistent with the locus ceruleus. Moreover, a psychophysiological interaction showed that amygdalar responses were more tightly related to those of the locus ceruleus when remembering faces that had been encoded in an emotional, rather than neutral, context. These findings suggest that the restoration of a central arousal similar to encoding takes part in the successful retrieval of neutral events learned in an emotional context.
ARTICLE UPDATE - Distributed and interactive brain mechanisms during emotion face perception: Evidence from functional neuroimaging.
Vuilleumier P, Pourtois G.
Neuropsychologia, in press
Brain imaging studies in humans have shown that face processing in several areas is modulated by the affective significance of faces, particularly with fearful expressions, but also with other social signals such gaze direction. Here we review haemodynamic and electrical neuroimaging results indicating that activity in the face-selective fusiform cortex may be enhanced by emotional (fearful) expressions, without explicit voluntary control, and presumably through direct feedback connections from the amygdala. fMRI studies show that these increased responses in fusiform cortex to fearful faces are abolished by amygdala damage in the ipsilateral hemisphere, despite preserved effects of voluntary attention on fusiform; whereas emotional increases can still arise despite deficits in attention or awareness following parietal damage, and appear relatively unaffected by pharmacological increases in cholinergic stimulation. Fear-related modulations of face processing driven by amygdala signals may implicate not only fusiform cortex, but also earlier visual areas in occipital cortex (e.g., V1) and other distant regions involved in social, cognitive, or somatic responses (e.g., superior temporal sulcus, cingulate, or parietal areas). In the temporal domain, evoked-potentials show a widespread time-course of emotional face perception, with some increases in the amplitude of responses recorded over both occipital and frontal regions for fearful relative to neutral faces (as well as in the amygdala and orbitofrontal cortex, when using intracranial recordings), but with different latencies post-stimulus onset. Early emotional responses may arise around 120ms, prior to a full visual categorization stage indexed by the face-selective N170 component, possibly reflecting rapid emotion processing based on crude visual cues in faces. Other electrical components arise at later latencies and involve more sustained activities, probably generated in associative or supramodal brain areas, and resulting in part from the modulatory signals received from amygdala. Altogether, these fMRI and ERP results demonstrate that emotion face perception is a complex process that cannot be related to a single neural event taking place in a single brain regions, but rather implicates an interactive network with distributed activity in time and space. Moreover, although traditional models in cognitive neuropsychology have often considered that facial expression and facial identity are processed along two separate pathways, evidence from fMRI and ERPs suggests instead that emotional processing can strongly affect brain systems responsible for face recognition and memory. The functional implications of these interactions remain to be fully explored, but might play an important role in the normal development of face processing skills and in some neuropsychiatric disorders.
Neuropsychologia, in press
Brain imaging studies in humans have shown that face processing in several areas is modulated by the affective significance of faces, particularly with fearful expressions, but also with other social signals such gaze direction. Here we review haemodynamic and electrical neuroimaging results indicating that activity in the face-selective fusiform cortex may be enhanced by emotional (fearful) expressions, without explicit voluntary control, and presumably through direct feedback connections from the amygdala. fMRI studies show that these increased responses in fusiform cortex to fearful faces are abolished by amygdala damage in the ipsilateral hemisphere, despite preserved effects of voluntary attention on fusiform; whereas emotional increases can still arise despite deficits in attention or awareness following parietal damage, and appear relatively unaffected by pharmacological increases in cholinergic stimulation. Fear-related modulations of face processing driven by amygdala signals may implicate not only fusiform cortex, but also earlier visual areas in occipital cortex (e.g., V1) and other distant regions involved in social, cognitive, or somatic responses (e.g., superior temporal sulcus, cingulate, or parietal areas). In the temporal domain, evoked-potentials show a widespread time-course of emotional face perception, with some increases in the amplitude of responses recorded over both occipital and frontal regions for fearful relative to neutral faces (as well as in the amygdala and orbitofrontal cortex, when using intracranial recordings), but with different latencies post-stimulus onset. Early emotional responses may arise around 120ms, prior to a full visual categorization stage indexed by the face-selective N170 component, possibly reflecting rapid emotion processing based on crude visual cues in faces. Other electrical components arise at later latencies and involve more sustained activities, probably generated in associative or supramodal brain areas, and resulting in part from the modulatory signals received from amygdala. Altogether, these fMRI and ERP results demonstrate that emotion face perception is a complex process that cannot be related to a single neural event taking place in a single brain regions, but rather implicates an interactive network with distributed activity in time and space. Moreover, although traditional models in cognitive neuropsychology have often considered that facial expression and facial identity are processed along two separate pathways, evidence from fMRI and ERPs suggests instead that emotional processing can strongly affect brain systems responsible for face recognition and memory. The functional implications of these interactions remain to be fully explored, but might play an important role in the normal development of face processing skills and in some neuropsychiatric disorders.
Friday, July 14, 2006
ARTICLE UPDATE - On rejecting emotional lures created by phonological neighborhood activation.
Starns JJ, Cook GI, Hicks JL, Marsh RL.
Journal of Experimental Psychology: Learning, Memory and Cognition, 32, 847-853.
The authors conducted 2 experiments to assess how phonologically related lures are rejected in a false memory paradigm. Some phonological lures were emotional (i.e., taboo) words, and others were not. The authors manipulated the presence of taboo items on the study list and reduced the ability to use controlled rejection strategies by dividing attention and forcing a short response deadline. The results converge on the idea that participants reduce false alarms to emotional lures by setting more stringent recognition criteria for these items based on their expected memorability. Additionally, emotional lures are less familiar than nonemotional lures because emotional lures have affective and semantic features that mismatch studied nonemotional items.
Journal of Experimental Psychology: Learning, Memory and Cognition, 32, 847-853.
The authors conducted 2 experiments to assess how phonologically related lures are rejected in a false memory paradigm. Some phonological lures were emotional (i.e., taboo) words, and others were not. The authors manipulated the presence of taboo items on the study list and reduced the ability to use controlled rejection strategies by dividing attention and forcing a short response deadline. The results converge on the idea that participants reduce false alarms to emotional lures by setting more stringent recognition criteria for these items based on their expected memorability. Additionally, emotional lures are less familiar than nonemotional lures because emotional lures have affective and semantic features that mismatch studied nonemotional items.
Monday, July 03, 2006
ARTICLE UPDATE - Temporal dynamics of face repetition suppression
Alumit Ishai, Philip C. Bikle and Leslie G. Ungerleider
Brain Research Bulletin, in press
Single-unit recordings and functional brain imaging studies have shown reduced neural responses to repeated stimuli in the visual cortex. Using MEG, we compared responses evoked by repetitions of neutral faces to those evoked by fearful faces, which were either task relevant (targets) or irrelevant (distracters). Faces evoked a bi-phasic response in extrastriate cortex, peaking at 160–185 ms and at 220–250 ms, with stronger responses to neutral faces at the earlier interval and stronger responses to fearful faces at the later interval. At both latencies, repetitions of neutral and fearful targets resulted in reduced amplitude of the MEG signal. Additionally, we found that the context in which targets were presented affected their processing: fearful distracters increased the responses evoked by both neutral and fearful targets. Our data indicate that valence enhancement and context effects can be detected in extrastriate visual cortex within 250 ms and that these processes likely reflect feedback from other regions.
Brain Research Bulletin, in press
Single-unit recordings and functional brain imaging studies have shown reduced neural responses to repeated stimuli in the visual cortex. Using MEG, we compared responses evoked by repetitions of neutral faces to those evoked by fearful faces, which were either task relevant (targets) or irrelevant (distracters). Faces evoked a bi-phasic response in extrastriate cortex, peaking at 160–185 ms and at 220–250 ms, with stronger responses to neutral faces at the earlier interval and stronger responses to fearful faces at the later interval. At both latencies, repetitions of neutral and fearful targets resulted in reduced amplitude of the MEG signal. Additionally, we found that the context in which targets were presented affected their processing: fearful distracters increased the responses evoked by both neutral and fearful targets. Our data indicate that valence enhancement and context effects can be detected in extrastriate visual cortex within 250 ms and that these processes likely reflect feedback from other regions.
Friday, June 30, 2006
ARTICLE UPDATE - Intentional modulation of emotional responding to unpleasant pictures: An ERP study.
Moser JS, Hajcak G, Bukay E, Simons RF.
Psychophysiology, 43, 292-296.
Intentionally altering responses to unpleasant stimuli affects physiological and hemodynamic activity associated with emotional and cognitive processing. In the present experiment, we measured the late-positive potential (LPP) of the visually evoked event-related brain potential to examine the effects of intentional emotion modulation on electrophysiological correlates of emotional and cognitive processing. Seventeen participants received instructions to view, suppress, and enhance emotional responses to unpleasant stimuli. Results revealed significantly decreased electrophysiological activity during suppression of emotional responses beginning around 250 ms poststimulus and lasting several hundred milliseconds. These data suggest that ERPs are sensitive to emotion modulation/regulation processes.
Psychophysiology, 43, 292-296.
Intentionally altering responses to unpleasant stimuli affects physiological and hemodynamic activity associated with emotional and cognitive processing. In the present experiment, we measured the late-positive potential (LPP) of the visually evoked event-related brain potential to examine the effects of intentional emotion modulation on electrophysiological correlates of emotional and cognitive processing. Seventeen participants received instructions to view, suppress, and enhance emotional responses to unpleasant stimuli. Results revealed significantly decreased electrophysiological activity during suppression of emotional responses beginning around 250 ms poststimulus and lasting several hundred milliseconds. These data suggest that ERPs are sensitive to emotion modulation/regulation processes.
Wednesday, June 28, 2006
ARTICLE UPDATE - Event-related brain potential correlates of emotional face processing
Martin Eimer and Amanda Holmes
Neuropsychologia, in press
Results from recent event-related brain potential (ERP) studies investigating brain processes involved in the detection and analysis of emotional facial expression are reviewed. In all experiments, emotional faces were found to trigger an increased ERP positivity relative to neutral faces. The onset of this emotional expression effect was remarkably early, ranging from 120 to 180 ms post-stimulus in different experiments where faces were either presented at fixation or laterally, and with or without non-face distractor stimuli. While broadly distributed positive deflections beyond 250 ms post-stimulus have been found in previous studies for non-face stimuli, the early frontocentrally distributed phase of this emotional positivity is most likely face-specific. Similar emotional expression effects were found for six basic emotions, suggesting that these effects are not primarily generated within neural structures specialised for the automatic detection of specific emotions. Expression effects were eliminated when attention was directed away from the location of peripherally presented emotional faces, indicating that they are not linked to pre-attentive emotional processing. When foveal faces were unattended, expression effects were attenuated, but not completely eliminated. It is suggested that these ERP correlates of emotional face processing reflect activity within a neocortical system where representations of emotional content are generated in a task-dependent fashion for the adaptive intentional control of behaviour. Given the early onset of the emotion-specific effects reviewed here, it is likely that this system is activated in parallel with the ongoing evaluation of emotional content in the amygdala and related subcortical brain circuits.
Neuropsychologia, in press
Results from recent event-related brain potential (ERP) studies investigating brain processes involved in the detection and analysis of emotional facial expression are reviewed. In all experiments, emotional faces were found to trigger an increased ERP positivity relative to neutral faces. The onset of this emotional expression effect was remarkably early, ranging from 120 to 180 ms post-stimulus in different experiments where faces were either presented at fixation or laterally, and with or without non-face distractor stimuli. While broadly distributed positive deflections beyond 250 ms post-stimulus have been found in previous studies for non-face stimuli, the early frontocentrally distributed phase of this emotional positivity is most likely face-specific. Similar emotional expression effects were found for six basic emotions, suggesting that these effects are not primarily generated within neural structures specialised for the automatic detection of specific emotions. Expression effects were eliminated when attention was directed away from the location of peripherally presented emotional faces, indicating that they are not linked to pre-attentive emotional processing. When foveal faces were unattended, expression effects were attenuated, but not completely eliminated. It is suggested that these ERP correlates of emotional face processing reflect activity within a neocortical system where representations of emotional content are generated in a task-dependent fashion for the adaptive intentional control of behaviour. Given the early onset of the emotion-specific effects reviewed here, it is likely that this system is activated in parallel with the ongoing evaluation of emotional content in the amygdala and related subcortical brain circuits.
ARTICLE UPDATE - Are you always on my mind? A review of how face perception and attention interact
Romina Palermo and Gillian Rhodes
Neuropsychologia, in press,
In this review we examine how attention is involved in detecting faces, recognizing facial identity and registering and discriminating between facial expressions of emotion. The first section examines whether these aspects of face perception are “automatic”, in that they are especially rapid, non-conscious, mandatory and capacity-free. The second section discusses whether limited-capacity selective attention mechanisms are preferentially recruited by faces and facial expressions. Evidence from behavioral, neuropsychological, neuroimaging and psychophysiological studies from humans and single-unit recordings from primates is examined and the neural systems involved in processing faces, emotion and attention are highlighted. Avenues for further research are identified.
Neuropsychologia, in press,
In this review we examine how attention is involved in detecting faces, recognizing facial identity and registering and discriminating between facial expressions of emotion. The first section examines whether these aspects of face perception are “automatic”, in that they are especially rapid, non-conscious, mandatory and capacity-free. The second section discusses whether limited-capacity selective attention mechanisms are preferentially recruited by faces and facial expressions. Evidence from behavioral, neuropsychological, neuroimaging and psychophysiological studies from humans and single-unit recordings from primates is examined and the neural systems involved in processing faces, emotion and attention are highlighted. Avenues for further research are identified.
Friday, June 16, 2006
ARTICLE UPDATE - The influence of nonremembered affective associations on preference.
Ghuman AS, Bar M.
Emotion, 6, 215-223.
An important influence on our preference toward a specific object is its associations with affective information. Here, the authors concentrate on the role of memory on shaping such preferences. Specifically, the authors used a multistage behavioral paradigm that fostered associations between neutral shapes and affective images. Participants that explicitly remembered these affective associations preferred neutral shapes associated with positive images. Counterintuitively, participants who could not explicitly remember the associations preferred neutral shapes that were associated with negative images. Generally, the difference in preference between participants who could and could not remember the affective associations demonstrates a critical link between memory and preference formation. The authors propose that the preference for negatively associated items is a manifestation of a mechanism that produces an inherent incentive for rapidly assessing potentially threatening aspects in the environment.
Emotion, 6, 215-223.
An important influence on our preference toward a specific object is its associations with affective information. Here, the authors concentrate on the role of memory on shaping such preferences. Specifically, the authors used a multistage behavioral paradigm that fostered associations between neutral shapes and affective images. Participants that explicitly remembered these affective associations preferred neutral shapes associated with positive images. Counterintuitively, participants who could not explicitly remember the associations preferred neutral shapes that were associated with negative images. Generally, the difference in preference between participants who could and could not remember the affective associations demonstrates a critical link between memory and preference formation. The authors propose that the preference for negatively associated items is a manifestation of a mechanism that produces an inherent incentive for rapidly assessing potentially threatening aspects in the environment.
ARTICLE UPDATE - Rapid picture presentation and affective engagement.
Smith JC, Low A, Bradley MM, Lang PJ.
Emotion, 6, 208-214.
Emotional reactions were assessed to pictorial stimuli presented in a continuous stream at rapid speeds that compromise conceptual memory and the processing of specific picture content. Blocks of unpleasant, neutral, or pleasant pictures were presented at the rate of either three pictures per second or seven pictures per second. Even with rapid presentation rates, startle reflexes, corrugator muscle activity, and skin conductance responses were heightened when viewing unpleasant pictures. These effects were stronger later in the aversive block, suggesting that cumulative exposure increasingly activates the defense system. The findings suggest that, despite conceptual masking inherent in rapid serial visual presentation, affective pictures prompt measurable emotional engagement.
Emotion, 6, 208-214.
Emotional reactions were assessed to pictorial stimuli presented in a continuous stream at rapid speeds that compromise conceptual memory and the processing of specific picture content. Blocks of unpleasant, neutral, or pleasant pictures were presented at the rate of either three pictures per second or seven pictures per second. Even with rapid presentation rates, startle reflexes, corrugator muscle activity, and skin conductance responses were heightened when viewing unpleasant pictures. These effects were stronger later in the aversive block, suggesting that cumulative exposure increasingly activates the defense system. The findings suggest that, despite conceptual masking inherent in rapid serial visual presentation, affective pictures prompt measurable emotional engagement.
ARTICLE UPDATE - Spontaneous retrieval of affective person knowledge in face perception.
Todorov A, Gobbini MI, Evans KK, Haxby JV.
Neuropsychologia, in press
In a functional magnetic resonance imaging experiment, we explored whether affective person knowledge based on memories formed from minimal information is spontaneously retrieved in face perception. In the first stage of the experiment, participants were presented with 120 unfamiliar faces. Each face was presented with a description of one of four types of behaviors: aggressive, disgusting, neutral, and nice. In the second stage, participants were scanned while engaged in a one-back recognition task in which they saw the faces that were associated with behaviors and 30 novel faces. Although this task is a simple perceptual task that neither demands person evaluation nor retrieval of person knowledge, neural responses to faces differed as a function of the behaviors. Faces associated with behaviors evoked stronger activity than did novel faces in regions implicated in social cognition-anterior paracingulate cortex and superior temporal sulcus. Explicit memory for the behaviors enhanced the neural response in these regions. Faces associated with disgusting behaviors evoked stronger activity in left anterior insula than did faces associated with aggressive behaviors. This effect was equally strong for faces associated with explicitly recalled behaviors and faces associated with non-recalled behaviors. The findings suggest that affective person knowledge acquired from minimal information is spontaneously retrieved in face perception, engaging neural systems for analysis of social cognition and emotions.
Neuropsychologia, in press
In a functional magnetic resonance imaging experiment, we explored whether affective person knowledge based on memories formed from minimal information is spontaneously retrieved in face perception. In the first stage of the experiment, participants were presented with 120 unfamiliar faces. Each face was presented with a description of one of four types of behaviors: aggressive, disgusting, neutral, and nice. In the second stage, participants were scanned while engaged in a one-back recognition task in which they saw the faces that were associated with behaviors and 30 novel faces. Although this task is a simple perceptual task that neither demands person evaluation nor retrieval of person knowledge, neural responses to faces differed as a function of the behaviors. Faces associated with behaviors evoked stronger activity than did novel faces in regions implicated in social cognition-anterior paracingulate cortex and superior temporal sulcus. Explicit memory for the behaviors enhanced the neural response in these regions. Faces associated with disgusting behaviors evoked stronger activity in left anterior insula than did faces associated with aggressive behaviors. This effect was equally strong for faces associated with explicitly recalled behaviors and faces associated with non-recalled behaviors. The findings suggest that affective person knowledge acquired from minimal information is spontaneously retrieved in face perception, engaging neural systems for analysis of social cognition and emotions.
ARTICLE UPDATE - Human and computer recognition of facial expressions of emotion.
Susskind JM, Littlewort G, Bartlett MS, Movellan J, Anderson AK.
Neuropsychologia, in press
Neuropsychological and neuroimaging evidence suggests that the human brain contains facial expression recognition detectors specialized for specific discrete emotions. However, some human behavioral data suggest that humans recognize expressions as similar and not discrete entities. This latter observation has been taken to indicate that internal representations of facial expressions may be best characterized as varying along continuous underlying dimensions. To examine the potential compatibility of these two views, the present study compared human and support vector machine (SVM) facial expression recognition performance. Separate SVMs were trained to develop fully automatic optimal recognition of one of six basic emotional expressions in real-time with no explicit training on expression similarity. Performance revealed high recognition accuracy for expression prototypes. Without explicit training of similarity detection, magnitude of activation across each emotion-specific SVM captured human judgments of expression similarity. This evidence suggests that combinations of expert classifiers from separate internal neural representations result in similarity judgments between expressions, supporting the appearance of a continuous underlying dimensionality. Further, these data suggest similarity in expression meaning is supported by superficial similarities in expression appearance.
Neuropsychologia, in press
Neuropsychological and neuroimaging evidence suggests that the human brain contains facial expression recognition detectors specialized for specific discrete emotions. However, some human behavioral data suggest that humans recognize expressions as similar and not discrete entities. This latter observation has been taken to indicate that internal representations of facial expressions may be best characterized as varying along continuous underlying dimensions. To examine the potential compatibility of these two views, the present study compared human and support vector machine (SVM) facial expression recognition performance. Separate SVMs were trained to develop fully automatic optimal recognition of one of six basic emotional expressions in real-time with no explicit training on expression similarity. Performance revealed high recognition accuracy for expression prototypes. Without explicit training of similarity detection, magnitude of activation across each emotion-specific SVM captured human judgments of expression similarity. This evidence suggests that combinations of expert classifiers from separate internal neural representations result in similarity judgments between expressions, supporting the appearance of a continuous underlying dimensionality. Further, these data suggest similarity in expression meaning is supported by superficial similarities in expression appearance.
Monday, June 12, 2006
ARTICLE UPDATE - Semantic Processing Precedes Affect Retrieval: The Neurological Case for Cognitive Primacy in Visual Processing
Justin Storbeck, Michael D. Robinson and Mark E. McCourt
Review of General Psychology, 10, 41-55.
According to the affective primacy hypothesis, visual stimuli can be evaluated prior to and independent of object identification and semantic analysis (Zajonc, 1980, 2000). Our review concludes that the affective primacy hypothesis is, from the available evidence, not likely correct. Although people can react to objects that they cannot consciously identify, such affective reactions are dependent upon prior semantic analysis within the visual cortex. The authors propose that the features of objects must first be integrated, and then the objects themselves must be categorized and identified, all prior to affective analysis. Additionally, the authors offer a preliminary neurological analysis of the mere exposure and affective priming effects that is consistent with the claim that semantic analysis is needed to elicit these effects. In sum, the authors conclude that the brain must know what something is in order to know whether it is good or bad.
Review of General Psychology, 10, 41-55.
According to the affective primacy hypothesis, visual stimuli can be evaluated prior to and independent of object identification and semantic analysis (Zajonc, 1980, 2000). Our review concludes that the affective primacy hypothesis is, from the available evidence, not likely correct. Although people can react to objects that they cannot consciously identify, such affective reactions are dependent upon prior semantic analysis within the visual cortex. The authors propose that the features of objects must first be integrated, and then the objects themselves must be categorized and identified, all prior to affective analysis. Additionally, the authors offer a preliminary neurological analysis of the mere exposure and affective priming effects that is consistent with the claim that semantic analysis is needed to elicit these effects. In sum, the authors conclude that the brain must know what something is in order to know whether it is good or bad.
Saturday, June 10, 2006
ARTICLE UPDATE - Functional neuroimaging of emotional learning and autonomic reactions
Martin Peper, Martin Herpers, Joachim Spreer, Jürgen Hennig and Josef Zentner
Journal of Psysiology - Paris, in press
This article provides a selective overview of the functional neuroimaging literature with an emphasis on emotional activation processes. Emotions are fast and flexible response systems that provide basic tendencies for adaptive action. From the range of involved component functions, we first discuss selected automatic mechanisms that control basic adaptational changes. Second, we illustrate how neuroimaging work has contributed to the mapping of the network components associated with basic emotion families (fear, anger, disgust, happiness), and secondary dimensional concepts that organise the meaning space for subjective experience and verbal labels (emotional valence, activity/intensity, approach/withdrawal, etc.). Third, results and methodological difficulties are discussed in view of own neuroimaging experiments that investigated the component functions involved in emotional learning. The amygdala, prefrontal cortex, and striatum form a network of reciprocal connections that show topographically distinct patterns of activity as a correlate of up and down regulation processes during an emotional episode. Emotional modulations of other brain systems have attracted recent research interests. Emotional neuroimaging calls for more representative designs that highlight the modulatory influences of regulation strategies and socio-cultural factors responsible for inhibitory control and extinction. We conclude by emphasising the relevance of the temporal process dynamics of emotional activations that may provide improved prediction of individual differences in emotionality.
Journal of Psysiology - Paris, in press
This article provides a selective overview of the functional neuroimaging literature with an emphasis on emotional activation processes. Emotions are fast and flexible response systems that provide basic tendencies for adaptive action. From the range of involved component functions, we first discuss selected automatic mechanisms that control basic adaptational changes. Second, we illustrate how neuroimaging work has contributed to the mapping of the network components associated with basic emotion families (fear, anger, disgust, happiness), and secondary dimensional concepts that organise the meaning space for subjective experience and verbal labels (emotional valence, activity/intensity, approach/withdrawal, etc.). Third, results and methodological difficulties are discussed in view of own neuroimaging experiments that investigated the component functions involved in emotional learning. The amygdala, prefrontal cortex, and striatum form a network of reciprocal connections that show topographically distinct patterns of activity as a correlate of up and down regulation processes during an emotional episode. Emotional modulations of other brain systems have attracted recent research interests. Emotional neuroimaging calls for more representative designs that highlight the modulatory influences of regulation strategies and socio-cultural factors responsible for inhibitory control and extinction. We conclude by emphasising the relevance of the temporal process dynamics of emotional activations that may provide improved prediction of individual differences in emotionality.
Friday, June 09, 2006
ARTICLE UPDATE - Fear Recognition Ability Predicts Differences in Social Cognitive and Neural Functioning in Men
Ben Corden, Hugo D. Critchley, David Skuse and Raymond J. Dolan
Journal of Cognitive Neuroscience, 18, 889-897.
By testing the facial fear-recognition ability of 341 men in the general population, we show that 8.8% have deficits akin to those seen with acquired amygdala damage. Using psychological tests and functional magnetic resonance imaging (fMRI) we tested the hypothesis that poor fear recognition would predict deficits in other domains of social cognition and, in response to socially relevant stimuli, abnormal activation in brain regions that putatively reflect engagement of the "social brain." On tests of "theory of mind" ability, 25 "low fear scorers" (LFS) performed significantly worse than 25 age- and IQ-matched "normal (good) fear scorers" (NFS). In fMRI, we compared evoked activity during a gender judgement task to neutral faces portraying different head and eye gaze orientations in 12 NFS and 12 LFS subjects. Despite identical between-group accuracy in gender discrimination, LFS demonstrated significantly reduced activation in amygdala, fusiform gyrus, and anterior superior temporal cortices when viewing faces with direct versus averted gaze. In a functional connectivity analysis, NFS show enhanced connectivity between the amygdala and anterior temporal cortex in the context of direct gaze; this enhanced coupling is absent in LFS. We suggest that important individual differences in social cognitive skills are expressed within the healthy male population, which appear to have a basis in a compromised neural system that underpins social information processing.
Journal of Cognitive Neuroscience, 18, 889-897.
By testing the facial fear-recognition ability of 341 men in the general population, we show that 8.8% have deficits akin to those seen with acquired amygdala damage. Using psychological tests and functional magnetic resonance imaging (fMRI) we tested the hypothesis that poor fear recognition would predict deficits in other domains of social cognition and, in response to socially relevant stimuli, abnormal activation in brain regions that putatively reflect engagement of the "social brain." On tests of "theory of mind" ability, 25 "low fear scorers" (LFS) performed significantly worse than 25 age- and IQ-matched "normal (good) fear scorers" (NFS). In fMRI, we compared evoked activity during a gender judgement task to neutral faces portraying different head and eye gaze orientations in 12 NFS and 12 LFS subjects. Despite identical between-group accuracy in gender discrimination, LFS demonstrated significantly reduced activation in amygdala, fusiform gyrus, and anterior superior temporal cortices when viewing faces with direct versus averted gaze. In a functional connectivity analysis, NFS show enhanced connectivity between the amygdala and anterior temporal cortex in the context of direct gaze; this enhanced coupling is absent in LFS. We suggest that important individual differences in social cognitive skills are expressed within the healthy male population, which appear to have a basis in a compromised neural system that underpins social information processing.
ARTICLE UPDATE - Orbitofrontal Cortex and Social Behavior: Integrating Self-monitoring and Emotion–Cognition Interactions
Jennifer S. Beer, Oliver P. John, Donatella Scabini and Robert T. Knight
Journal of Cognitive Neuroscience, 18, 871-879.
The role of the orbitofrontal cortex in social behavior remains a puzzle. Various theories of the social functions of the orbitofrontal cortex focus on the role of this area in either emotional processing or its involvement in online monitoring of behavior (i.e., self-monitoring). The present research attempts to integrate these two theories by examining whether improving the self-monitoring of patients with orbitofrontal damage is associated with the generation of emotions needed to guide interpersonal behavior. Patients with orbitofrontal damage, patients with lateral prefrontal damage, and healthy controls took part in an interpersonal task. After completing the task, participants' self-monitoring was increased by showing them a videotape of their task performance. In comparison to healthy controls and patients with lateral prefrontal damage, orbitofrontal damage was associated with objectively inappropriate social behavior. Although patients with orbitofrontal damage were aware of social norms of intimacy, they were unaware that their task performance violated these norms. The embarrassment typically associated with inappropriate social behavior was elicited in these patients only after their self-monitoring increased from viewing their videotaped performance. These findings suggest that damage to the orbitofrontal cortex impairs self-insight that may preclude the generation of helpful emotional information. The results highlight the role of the orbitofrontal cortex in the interplay of self-monitoring and emotional processing and suggest avenues for neurorehabilitation of patients with social deficits subsequent to orbitofrontal damage.
Journal of Cognitive Neuroscience, 18, 871-879.
The role of the orbitofrontal cortex in social behavior remains a puzzle. Various theories of the social functions of the orbitofrontal cortex focus on the role of this area in either emotional processing or its involvement in online monitoring of behavior (i.e., self-monitoring). The present research attempts to integrate these two theories by examining whether improving the self-monitoring of patients with orbitofrontal damage is associated with the generation of emotions needed to guide interpersonal behavior. Patients with orbitofrontal damage, patients with lateral prefrontal damage, and healthy controls took part in an interpersonal task. After completing the task, participants' self-monitoring was increased by showing them a videotape of their task performance. In comparison to healthy controls and patients with lateral prefrontal damage, orbitofrontal damage was associated with objectively inappropriate social behavior. Although patients with orbitofrontal damage were aware of social norms of intimacy, they were unaware that their task performance violated these norms. The embarrassment typically associated with inappropriate social behavior was elicited in these patients only after their self-monitoring increased from viewing their videotaped performance. These findings suggest that damage to the orbitofrontal cortex impairs self-insight that may preclude the generation of helpful emotional information. The results highlight the role of the orbitofrontal cortex in the interplay of self-monitoring and emotional processing and suggest avenues for neurorehabilitation of patients with social deficits subsequent to orbitofrontal damage.
ARTICLE UPDATE - Neural systems connecting interoceptive awareness and feelings.
Pollatos O, Gramann K, Schandry R.
Human Brain Mapping, in press
In many theories of emotions the representations of bodily responses play an important role for subjective feelings. We tested the hypothesis that the perception of bodily states is positively related to the experienced intensity of feelings as well as to the activity of first-order and second-order brain structures involved in the processing of feelings. Using a heartbeat perception task, subjects were separated into groups with either high or poor interoceptive awareness. During emotional picture presentation we measured high-density EEG and used spatiotemporal current density reconstruction to identify regions involved in both interoceptive awareness and emotion processing. We observed a positive relation between interoceptive awareness and the experienced intensity of emotions. Furthermore, the P300 amplitudes to pleasant and unpleasant pictures were enhanced for subjects with high interoceptive awareness. The source reconstruction revealed that interoceptive awareness is related to an enhanced activation in both first-order structures (insula, somatosensory cortices) and second-order structures (anterior cingulate, prefrontal cortices). We conclude that the perception of bodily states is a crucial determinant for the processing and the subjective experience of feelings.
Human Brain Mapping, in press
In many theories of emotions the representations of bodily responses play an important role for subjective feelings. We tested the hypothesis that the perception of bodily states is positively related to the experienced intensity of feelings as well as to the activity of first-order and second-order brain structures involved in the processing of feelings. Using a heartbeat perception task, subjects were separated into groups with either high or poor interoceptive awareness. During emotional picture presentation we measured high-density EEG and used spatiotemporal current density reconstruction to identify regions involved in both interoceptive awareness and emotion processing. We observed a positive relation between interoceptive awareness and the experienced intensity of emotions. Furthermore, the P300 amplitudes to pleasant and unpleasant pictures were enhanced for subjects with high interoceptive awareness. The source reconstruction revealed that interoceptive awareness is related to an enhanced activation in both first-order structures (insula, somatosensory cortices) and second-order structures (anterior cingulate, prefrontal cortices). We conclude that the perception of bodily states is a crucial determinant for the processing and the subjective experience of feelings.
ARTICLE UPDATE - Hemispheric asymmetries for the conscious and unconscious perception of emotional words
Smith SD, Bulman-Fleming MB.
Laterality, 11, 304-330.
The current research examines the interactions between hemispheric asymmetries for visual perception and emotion. In a series of four experiments, participants completed tasks measuring both conscious and unconscious perception of linguistic stimuli. In these studies, stimulus-presentation parameters (brief exposure duration vs masking) and the emotional valence of the test stimuli (negative vs positive) were manipulated in order to create studies in which the visual and emotional asymmetries were congruent (favoured the same hemispheres) or were incongruent (favoured opposing hemispheres). The results demonstrated that negative emotional stimuli led to a right-hemisphere advantage for conscious perception only when stimuli were shown for brief exposures (17 ms). Positive emotional words did not elicit hemispheric asymmetries. The results are discussed in terms of their relevance for theories of emotional lateralisation.
Laterality, 11, 304-330.
The current research examines the interactions between hemispheric asymmetries for visual perception and emotion. In a series of four experiments, participants completed tasks measuring both conscious and unconscious perception of linguistic stimuli. In these studies, stimulus-presentation parameters (brief exposure duration vs masking) and the emotional valence of the test stimuli (negative vs positive) were manipulated in order to create studies in which the visual and emotional asymmetries were congruent (favoured the same hemispheres) or were incongruent (favoured opposing hemispheres). The results demonstrated that negative emotional stimuli led to a right-hemisphere advantage for conscious perception only when stimuli were shown for brief exposures (17 ms). Positive emotional words did not elicit hemispheric asymmetries. The results are discussed in terms of their relevance for theories of emotional lateralisation.
Thursday, May 25, 2006
ARTICLE UPDATE - Neural response to sustained affective visual stimulation using an indirect task
Carretie L, Hinojosa JA, Albert J, Mercado F.
Experimental Brain Research, in press
Event-related potentials were recorded from 30 subjects using sustained stimulation and an indirect task, two strategies which facilitate affective responses that are complete and free of cognitive interference. Stimuli were of three types: pleasant, unpleasant and neutral. A three-phase pattern was found. The first phase, an amplitude increase in response to negative stimuli higher than to neutral and pleasant stimuli, was produced at 160 ms after stimulus onset, the prefrontal cortex being the origin of this phase. The second phase, characterized by maximal amplitudes in response to positive stimuli, was produced at 400 ms, originating in the visual cortex. Finally, the third phase, another amplitude increase in response to negative stimuli, was produced at 680 ms, and its source was located in the left precentral gyrus. Present data show that the cortical response to sustained emotional visual stimulation presented within indirect tasks provides information on attention-, motivation- and motor-related biases that complement information obtained under other experimental conditions.
Experimental Brain Research, in press
Event-related potentials were recorded from 30 subjects using sustained stimulation and an indirect task, two strategies which facilitate affective responses that are complete and free of cognitive interference. Stimuli were of three types: pleasant, unpleasant and neutral. A three-phase pattern was found. The first phase, an amplitude increase in response to negative stimuli higher than to neutral and pleasant stimuli, was produced at 160 ms after stimulus onset, the prefrontal cortex being the origin of this phase. The second phase, characterized by maximal amplitudes in response to positive stimuli, was produced at 400 ms, originating in the visual cortex. Finally, the third phase, another amplitude increase in response to negative stimuli, was produced at 680 ms, and its source was located in the left precentral gyrus. Present data show that the cortical response to sustained emotional visual stimulation presented within indirect tasks provides information on attention-, motivation- and motor-related biases that complement information obtained under other experimental conditions.
ARTICLE UPDATE - Processing of emotional adjectives: Evidence from startle EMG and ERPs.
Herbert C, Kissler J, Junghofer M, Peyk P, Rockstroh B.
Psychophysiology, 43, 197-206
Affective startle modulation in the electromyographic (EMG), auditory startle evoked potentials, and visually evoked potentials (VEPs) were assessed while subjects evaluated pleasant, unpleasant, and neutral adjectives. Acoustic startle probes were presented at random time points 2.5-4.0 s after word onset. The visual P2 and P3 potentials were generally larger during processing of emotional than of neutral adjectives. In contrast, the late positive component was enhanced and was correlated with larger EMG startle responses and auditory startle evoked potential P3 amplitudes for pleasant words only. During internal cognitive activity, the startle reflex represents a measure of "processing interrupt." Thus the startle tone interrupted processing of particularly pleasant adjectives and caused re-alerting to environmental stimuli. Specific effects for pleasant material may arise from a "positivity offset," favoring responses to pleasant material at lower arousal levels.
Psychophysiology, 43, 197-206
Affective startle modulation in the electromyographic (EMG), auditory startle evoked potentials, and visually evoked potentials (VEPs) were assessed while subjects evaluated pleasant, unpleasant, and neutral adjectives. Acoustic startle probes were presented at random time points 2.5-4.0 s after word onset. The visual P2 and P3 potentials were generally larger during processing of emotional than of neutral adjectives. In contrast, the late positive component was enhanced and was correlated with larger EMG startle responses and auditory startle evoked potential P3 amplitudes for pleasant words only. During internal cognitive activity, the startle reflex represents a measure of "processing interrupt." Thus the startle tone interrupted processing of particularly pleasant adjectives and caused re-alerting to environmental stimuli. Specific effects for pleasant material may arise from a "positivity offset," favoring responses to pleasant material at lower arousal levels.
ARTICLE UPDATE - When does size not matter? Effects of stimulus size on affective modulation.
De Cesarei A, Codispoti M.
Psychophysiology, 43, 207-215.
Motivationally relevant stimuli have been shown to receive prioritized processing compared to neutral stimuli at distinct processing stages. This effect has been related to the evolutionary importance of rapidly detecting dangers and potential rewards and has been shown to be modulated by the distance between an organism and a faced stimulus. Similarly, recent studies showed degrees of emotional modulation of autonomic responses and subjective arousal ratings depending on stimulus size. In the present study, affective modulation of pictures presented in different sizes was investigated by measuring event-related potentials during a two-choice categorization task. Results showed significant emotional modulation across all sizes at both earlier and later stages of processing. Moreover, affective modulation of earlier processes was reduced in smaller compared to larger sizes, whereas no changes in affective modulation were observed at later stages.
Psychophysiology, 43, 207-215.
Motivationally relevant stimuli have been shown to receive prioritized processing compared to neutral stimuli at distinct processing stages. This effect has been related to the evolutionary importance of rapidly detecting dangers and potential rewards and has been shown to be modulated by the distance between an organism and a faced stimulus. Similarly, recent studies showed degrees of emotional modulation of autonomic responses and subjective arousal ratings depending on stimulus size. In the present study, affective modulation of pictures presented in different sizes was investigated by measuring event-related potentials during a two-choice categorization task. Results showed significant emotional modulation across all sizes at both earlier and later stages of processing. Moreover, affective modulation of earlier processes was reduced in smaller compared to larger sizes, whereas no changes in affective modulation were observed at later stages.
ARTICLE UPDATE - Differential time course and intensity of PFC activation for men and women in response to emotional stimuli: A functional near-infrar
Leon-Carrion J, Damas J, Izzetoglu K, Pourrezai K, Martin-Rodriguez JF, Martin JM, Dominguez-Morales MR.
Neuroscience Letters, in press
Using functional near-infrared spectroscopy (fNIRS) we recorded prefrontal cortex (PFC) activation during positive, negative and neutral film clips, based on affective ratings according to their valence and arousal, to assess gender differences in cerebral activation in 15 male and 15 female volunteers. To record PFC activation, five movie clips were presented on a 17-in. TFT screen. The recordings included a pre-stimulus 5-s local baseline and "on" and "off" segments of data, referring to fNIRS Oxy-Hb levels while stimulation (movie clip) was present and during an inter-stimulus blank screen. Our data showed gender differences in the delay period to initial PFC activation and in the course and intensity of activation produced by affective visual stimuli. During the exposure or "on" period of the stimuli we observed more pronounced overshoot and undershoot in men versus women across the range of emotions elicited. This effect was even more pronounced following stimulus cessation ("off" period). The results indicate that gender and the duration of recordings may affect the results of emotional neuroimaging studies
Neuroscience Letters, in press
Using functional near-infrared spectroscopy (fNIRS) we recorded prefrontal cortex (PFC) activation during positive, negative and neutral film clips, based on affective ratings according to their valence and arousal, to assess gender differences in cerebral activation in 15 male and 15 female volunteers. To record PFC activation, five movie clips were presented on a 17-in. TFT screen. The recordings included a pre-stimulus 5-s local baseline and "on" and "off" segments of data, referring to fNIRS Oxy-Hb levels while stimulation (movie clip) was present and during an inter-stimulus blank screen. Our data showed gender differences in the delay period to initial PFC activation and in the course and intensity of activation produced by affective visual stimuli. During the exposure or "on" period of the stimuli we observed more pronounced overshoot and undershoot in men versus women across the range of emotions elicited. This effect was even more pronounced following stimulus cessation ("off" period). The results indicate that gender and the duration of recordings may affect the results of emotional neuroimaging studies
ARTICLE UPDATE - A novel set-shifting modification of the iowa gambling task: flexible emotion-based learning in schizophrenia.
Turnbull OH, Evans CE, Kemish K, Park S, Bowman CH.
Neuropsychology, 20, 290-298.
Although it might seem that people with schizophrenia would perform poorly on measures of emotion-based learning, several studies have shown normal levels of performance on the Iowa Gambling Task (IGT; C. E. Y. Evans, C. H. Bowman, & O. H. Turnbull, 2005; L. M. Ritter, J. H. Meador-Woodruff, & G. W. Dalack, 2004; B. Shurman, W. P. Horan, & K. H. Nuechterlein, 2005; K. E. Wilder, D. R. Weinberger, & T. E. Goldberg, 1998). The present article describes a newly developed modification of the IGT involving initial familiarization with the basic contingency pattern then 3 periods of contingency shift. Control participants showed substantial gains during the later trials of each shift period. Analyzed in terms of positive symptoms, those with schizophrenia were little different from control participants. Those high in negative symptoms could perform the basic task but showed remarkably poor performances (no better than chance) in the shift phases, retaining a preference for decks that had previously been "good," even when they experienced substantial losses.
Neuropsychology, 20, 290-298.
Although it might seem that people with schizophrenia would perform poorly on measures of emotion-based learning, several studies have shown normal levels of performance on the Iowa Gambling Task (IGT; C. E. Y. Evans, C. H. Bowman, & O. H. Turnbull, 2005; L. M. Ritter, J. H. Meador-Woodruff, & G. W. Dalack, 2004; B. Shurman, W. P. Horan, & K. H. Nuechterlein, 2005; K. E. Wilder, D. R. Weinberger, & T. E. Goldberg, 1998). The present article describes a newly developed modification of the IGT involving initial familiarization with the basic contingency pattern then 3 periods of contingency shift. Control participants showed substantial gains during the later trials of each shift period. Analyzed in terms of positive symptoms, those with schizophrenia were little different from control participants. Those high in negative symptoms could perform the basic task but showed remarkably poor performances (no better than chance) in the shift phases, retaining a preference for decks that had previously been "good," even when they experienced substantial losses.
Friday, May 12, 2006
ARTICLE UPDATE - Enhanced perceptual priming for neutral stimuli occurring in a traumatic context: Two experimental investigations
T. Michael and A. Ehlers
Brain Research and Therapy, in press
Intrusive memories in posttraumatic stress disorder are often triggered by stimuli that are perceptually similar to those present shortly before or during the trauma. The present study aims to examine the possible role of perceptual priming in this phenomenon. It further investigates whether the degree of perceptual priming is associated with dissociation and whether both perceptual priming and intrusive memories can be reduced through elaboration.
Two experiments measured perceptual priming for neutral stimuli that immediately preceded a “traumatic” event. Volunteers (N=46, 92) watched a series of “traumatic” and neutral picture stories, and completed a blurred object identification (perceptual priming) memory task, and a recognition memory task. Participants in Experiment 1 were selected to score either high or low on the Trait Dissociation Questionnaire [Murray, Ehlers, & Mayou (2002). Dissociation and posttraumatic stress disorder: Two prospective studies of motor vehicle accident survivors. British Journal of Psychiatry, 180, 363–368]. They also completed a state dissociation measure in the session. Experiment 2 randomly allocated participants to an experimental condition designed to increase elaboration or to a control condition. This experiment also included a measure of intrusive memories.
Both experiments found enhanced perceptual priming for the stimuli that immediately preceded the “traumatic” stories compared to those preceding neutral stories. Participants with high trait dissociation showed relatively stronger perceptual perceptual priming. The degree of perceptual priming for stimuli from the “traumatic” stories also correlated with state dissociation (Experiment 1). Experimental manipulation of the elaboration of the stories showed that elaboration reduced the enhanced perceptual priming effect and the relative probability of reexperiencing symptoms (Experiment 2). The results support the role of perceptual priming in intrusions after traumatic events.
Brain Research and Therapy, in press
Intrusive memories in posttraumatic stress disorder are often triggered by stimuli that are perceptually similar to those present shortly before or during the trauma. The present study aims to examine the possible role of perceptual priming in this phenomenon. It further investigates whether the degree of perceptual priming is associated with dissociation and whether both perceptual priming and intrusive memories can be reduced through elaboration.
Two experiments measured perceptual priming for neutral stimuli that immediately preceded a “traumatic” event. Volunteers (N=46, 92) watched a series of “traumatic” and neutral picture stories, and completed a blurred object identification (perceptual priming) memory task, and a recognition memory task. Participants in Experiment 1 were selected to score either high or low on the Trait Dissociation Questionnaire [Murray, Ehlers, & Mayou (2002). Dissociation and posttraumatic stress disorder: Two prospective studies of motor vehicle accident survivors. British Journal of Psychiatry, 180, 363–368]. They also completed a state dissociation measure in the session. Experiment 2 randomly allocated participants to an experimental condition designed to increase elaboration or to a control condition. This experiment also included a measure of intrusive memories.
Both experiments found enhanced perceptual priming for the stimuli that immediately preceded the “traumatic” stories compared to those preceding neutral stories. Participants with high trait dissociation showed relatively stronger perceptual perceptual priming. The degree of perceptual priming for stimuli from the “traumatic” stories also correlated with state dissociation (Experiment 1). Experimental manipulation of the elaboration of the stories showed that elaboration reduced the enhanced perceptual priming effect and the relative probability of reexperiencing symptoms (Experiment 2). The results support the role of perceptual priming in intrusions after traumatic events.
ARTICLE UPDATE - Simultaneous masking in a dichotic emotion detection task
Daniel Voyer, Mariana Soraggi, Brandy Brake and Heather-Dawn Wood
Brain and Cognition, in press
The present study investigated the possible role of ceiling effects in producing laterality effects of small magnitude in dichotic emotion detection. Twenty two right-handed undergraduate students participated in the present experiment. They were required to detect the presence of a target emotion in the expressions tones of happiness, sadness, anger, and neutrality presented dichotically. Stimuli were adjusted to 70 dB and occurred simultaneously with a white noise mask that had an intensity of 65, 70, 80, or 85 dB. Results showed a left ear advantage (LEA) for the 65 dB mask and a right ear advantage for the 85 dB mask, but only after two testing sessions. The possible existence of a generalized right ear bias that might affect the observed LEA for non-verbal tasks is discussed. Alternative explanations and limitations of the present experiment are also presented.
Brain and Cognition, in press
The present study investigated the possible role of ceiling effects in producing laterality effects of small magnitude in dichotic emotion detection. Twenty two right-handed undergraduate students participated in the present experiment. They were required to detect the presence of a target emotion in the expressions tones of happiness, sadness, anger, and neutrality presented dichotically. Stimuli were adjusted to 70 dB and occurred simultaneously with a white noise mask that had an intensity of 65, 70, 80, or 85 dB. Results showed a left ear advantage (LEA) for the 65 dB mask and a right ear advantage for the 85 dB mask, but only after two testing sessions. The possible existence of a generalized right ear bias that might affect the observed LEA for non-verbal tasks is discussed. Alternative explanations and limitations of the present experiment are also presented.
ARTICLE UPDATE - Amygdala activation during masked presentation of emotional faces predicts conscious detection of threat-related faces
Thomas Suslow, Patricia Ohrmann, Jochen Bauer, Astrid Veronika Rauch, Wolfram Schwindt, Volker Arolt, Walter Heindel and Harald Kugel
Brain and Cognition, in press
It has been argued that critical functions of the human amygdala are to modulate the moment-to-moment vigilance level and to enhance the processing and the consolidation of memories of emotionally arousing material. In this functional magnetic resonance study, pictures of human faces bearing fearful, angry, and happy expressions were presented to nine healthy volunteers using a backward masking procedure based on neutral facial expression. Activation of the left and right amygdala in response to the masked fearful faces (compared to neutral faces) was significantly correlated with the number of fearful faces detected. In addition, right but not left amygdala activation in response to the masked angry faces was significantly related to the number of angry faces detected. The present findings underscore the role of the amygdala in the detection and consolidation of memory for marginally perceptible threatening facial expression.
Brain and Cognition, in press
It has been argued that critical functions of the human amygdala are to modulate the moment-to-moment vigilance level and to enhance the processing and the consolidation of memories of emotionally arousing material. In this functional magnetic resonance study, pictures of human faces bearing fearful, angry, and happy expressions were presented to nine healthy volunteers using a backward masking procedure based on neutral facial expression. Activation of the left and right amygdala in response to the masked fearful faces (compared to neutral faces) was significantly correlated with the number of fearful faces detected. In addition, right but not left amygdala activation in response to the masked angry faces was significantly related to the number of angry faces detected. The present findings underscore the role of the amygdala in the detection and consolidation of memory for marginally perceptible threatening facial expression.
ARTICLE UPDATE - Controlling the integration of emotion and cognition.
Beer JS, Knight RT, D'Esposito M.
Psychological Science, 17, 448-453.
Emotion has been both lauded and vilified for its role in decision making. How are people able to ensure that helpful emotions guide decision making and irrelevant emotions are kept out of decision making? The orbitofrontal cortex has been identified as a neural area involved in incorporating emotion into decision making. Is this area's function specific to the integration of emotion and cognition, or does it more broadly govern whether emotional information should be integrated into cognition? The present research examined the role of orbitofrontal cortex when it was appropriate to control (i.e., prevent) the influence of emotion in decision making (Experiment 1) and to incorporate the influence of emotion in decision making (Experiment 2). Together, the two studies suggest that activity in lateral orbitofrontal cortex is associated with evaluating the contextual relevance of emotional information for decision making.
Psychological Science, 17, 448-453.
Emotion has been both lauded and vilified for its role in decision making. How are people able to ensure that helpful emotions guide decision making and irrelevant emotions are kept out of decision making? The orbitofrontal cortex has been identified as a neural area involved in incorporating emotion into decision making. Is this area's function specific to the integration of emotion and cognition, or does it more broadly govern whether emotional information should be integrated into cognition? The present research examined the role of orbitofrontal cortex when it was appropriate to control (i.e., prevent) the influence of emotion in decision making (Experiment 1) and to incorporate the influence of emotion in decision making (Experiment 2). Together, the two studies suggest that activity in lateral orbitofrontal cortex is associated with evaluating the contextual relevance of emotional information for decision making.
Tuesday, May 09, 2006
ARTICLE UPDATE - Nonconscious semantic processing of emotional words modulates conscious access
Raphaël Gaillard, Antoine Del Cul, Lionel Naccache, Fabien Vinckier, Laurent Cohen, and Stanislas Dehaene
PNAS, 103, 7524-7529
Whether masked words can be processed at a semantic level remains a controversial issue in cognitive psychology. Although recent behavioral studies have demonstrated masked semantic priming for number words, attempts to generalize this finding to other categories of words have failed. Here, as an alternative to subliminal priming, we introduce a sensitive behavioral method to detect nonconscious semantic processing of words. The logic of this method consists of presenting words close to the threshold for conscious perception and examining whether their semantic content modulates performance in objective and subjective tasks. Our results disclose two independent sources of modulation of the threshold for access to consciousness. First, prior conscious perception of words increases the detection rate of the same words when they are subsequently presented with stronger masking. Second, the threshold for conscious access is lower for emotional words than for neutral ones, even for words that have not been previously consciously perceived, thus implying that written words can receive nonconscious semantic processing.
PNAS, 103, 7524-7529
Whether masked words can be processed at a semantic level remains a controversial issue in cognitive psychology. Although recent behavioral studies have demonstrated masked semantic priming for number words, attempts to generalize this finding to other categories of words have failed. Here, as an alternative to subliminal priming, we introduce a sensitive behavioral method to detect nonconscious semantic processing of words. The logic of this method consists of presenting words close to the threshold for conscious perception and examining whether their semantic content modulates performance in objective and subjective tasks. Our results disclose two independent sources of modulation of the threshold for access to consciousness. First, prior conscious perception of words increases the detection rate of the same words when they are subsequently presented with stronger masking. Second, the threshold for conscious access is lower for emotional words than for neutral ones, even for words that have not been previously consciously perceived, thus implying that written words can receive nonconscious semantic processing.
ARTICLE UPDATE - Mood-congruent free recall bias in anxious individuals is not a consequence of response bias
Russo, Riccardo, Whittuck, Dora, Roberson, Debi, Dutton, Kevin, Georgiou, George, Fox, Elaine
Memory, 14, 393-399.
The status of mood-congruent free recall bias in anxious individuals was evaluated following incidental encoding of target words. Individuals with high and low levels of trait anxiety completed a modified Stroop task, which revealed an attentional bias for threat-related stimuli in anxious individuals. This group was significantly slower in naming the colour in which threat-related words were displayed compared to neutral words. In a subsequent free recall test for the words used in the modified Stroop task, anxious individuals recalled more threat-related words compared to low-anxious people. This difference was significant even when controlling for the false recall of items that had not been presented during study. These results support the view put forward by Russo, Fox, Bellinger, and Nguyen-Van-Tam (2001) that mood-congruent free recall bias in anxious individuals can be observed if the target material is encoded at a relatively shallow level. Moreover, contrary to Dowens and Calvo (2003), the current results show that the memory advantage for threat-related information in anxious individuals is not a consequence of response bias.
Memory, 14, 393-399.
The status of mood-congruent free recall bias in anxious individuals was evaluated following incidental encoding of target words. Individuals with high and low levels of trait anxiety completed a modified Stroop task, which revealed an attentional bias for threat-related stimuli in anxious individuals. This group was significantly slower in naming the colour in which threat-related words were displayed compared to neutral words. In a subsequent free recall test for the words used in the modified Stroop task, anxious individuals recalled more threat-related words compared to low-anxious people. This difference was significant even when controlling for the false recall of items that had not been presented during study. These results support the view put forward by Russo, Fox, Bellinger, and Nguyen-Van-Tam (2001) that mood-congruent free recall bias in anxious individuals can be observed if the target material is encoded at a relatively shallow level. Moreover, contrary to Dowens and Calvo (2003), the current results show that the memory advantage for threat-related information in anxious individuals is not a consequence of response bias.
ARTICLE UPDATE - Modulation of the C1 Visual Event-related Component by Conditioned Stimuli: Evidence for Sensory Plasticity in Early Affective Percep
Margarita Stolarova, Andreas Keil and Stephan Moratti
Cerebral Cortex, 16, 876-887
Previous research has demonstrated optimized processing of motivationally significant stimuli early in perception. In the present study, the time course and underlying mechanisms for such fast differentiation are of interest. We investigated the involvement of the primary visual cortex in affective evaluation of conditioned stimuli (CSs). In order to elicit learning within the visual system we chose affective pictures as unconditioned stimuli and used laterally presented gratings as CSs. Using high-density electroencephalography, we demonstrated modulation of the C1 visual event-related component for threat-related stimuli versus neutral stimuli, which increased with continuing acquisition of affective meaning. The differentiation between aversive and neutral visual stimuli occurred as early as 65–90 ms after stimulus onset and suggested involvement of the primary visual areas in affective evaluation. As an underlying mechanism, we discuss short-term reorganization in visual cortex, enabling sensory amplification of specific visual features that are related to motivationally relevant information.
Cerebral Cortex, 16, 876-887
Previous research has demonstrated optimized processing of motivationally significant stimuli early in perception. In the present study, the time course and underlying mechanisms for such fast differentiation are of interest. We investigated the involvement of the primary visual cortex in affective evaluation of conditioned stimuli (CSs). In order to elicit learning within the visual system we chose affective pictures as unconditioned stimuli and used laterally presented gratings as CSs. Using high-density electroencephalography, we demonstrated modulation of the C1 visual event-related component for threat-related stimuli versus neutral stimuli, which increased with continuing acquisition of affective meaning. The differentiation between aversive and neutral visual stimuli occurred as early as 65–90 ms after stimulus onset and suggested involvement of the primary visual areas in affective evaluation. As an underlying mechanism, we discuss short-term reorganization in visual cortex, enabling sensory amplification of specific visual features that are related to motivationally relevant information.
Monday, May 08, 2006
ARTICLE UPDATE - Dissociation of event-related potentials indexing arousal and semantic cohesion during emotional word encoding
Daniel G. Dillon, Julie J. Cooper, Tineke Grent-‘t-Jong, Marty G. Woldorff and Kevin S. LaBar
Brain and Cognition, in press
Event-related potential (ERP) studies have shown that emotional stimuli elicit greater amplitude late positive-polarity potentials (LPPs) than neutral stimuli. This effect has been attributed to arousal, but emotional stimuli are also more semantically coherent than uncategorized neutral stimuli. ERPs were recorded during encoding of positive, negative, uncategorized neutral, and categorized neutral words. Differences in LPP amplitude elicited by emotional versus uncategorized neutral stimuli were evident from 450 to 1000 ms. From 450 to 700 ms, LPP effects at midline and right hemisphere frontal electrodes indexed arousal, whereas LPP effects at left hemisphere centro-parietal electrodes indexed semantic cohesion. This dissociation helps specify the processes underlying emotional stimulus encoding, and suggests the need to control for semantic cohesion in emotional information processing studies.
Brain and Cognition, in press
Event-related potential (ERP) studies have shown that emotional stimuli elicit greater amplitude late positive-polarity potentials (LPPs) than neutral stimuli. This effect has been attributed to arousal, but emotional stimuli are also more semantically coherent than uncategorized neutral stimuli. ERPs were recorded during encoding of positive, negative, uncategorized neutral, and categorized neutral words. Differences in LPP amplitude elicited by emotional versus uncategorized neutral stimuli were evident from 450 to 1000 ms. From 450 to 700 ms, LPP effects at midline and right hemisphere frontal electrodes indexed arousal, whereas LPP effects at left hemisphere centro-parietal electrodes indexed semantic cohesion. This dissociation helps specify the processes underlying emotional stimulus encoding, and suggests the need to control for semantic cohesion in emotional information processing studies.
Friday, May 05, 2006
ARTICLE UPDATE - Effects of picture content and intensity on affective physiological response.
Bernat E, Patrick CJ, Benning SD, Tellegen A.
Psychophysiology, 43, 93-103
Abstract This study evaluated the effects of affective intensity and thematic content of foreground photographic stimuli on various physiological response systems. This was accomplished by assessing responses to pictures that varied systematically in these parameters. Along with overall effects of picture valence reported in previous work, we found effects of thematic content (i.e., specific nature of objects/events depicted) for all measures except heart rate. In addition, we found that the magnitude of startle blink, skin conductance, and corrugator muscle reactions increased with increasing affective intensity of pictures. Additionally, for these three measures, intensity effects also interacted with effects of picture content. These results indicate that stimulus parameters of intensity and thematic content exert separate-and in some cases interactive-modulatory effects on physiological reactions to emotional pictures.
Psychophysiology, 43, 93-103
Abstract This study evaluated the effects of affective intensity and thematic content of foreground photographic stimuli on various physiological response systems. This was accomplished by assessing responses to pictures that varied systematically in these parameters. Along with overall effects of picture valence reported in previous work, we found effects of thematic content (i.e., specific nature of objects/events depicted) for all measures except heart rate. In addition, we found that the magnitude of startle blink, skin conductance, and corrugator muscle reactions increased with increasing affective intensity of pictures. Additionally, for these three measures, intensity effects also interacted with effects of picture content. These results indicate that stimulus parameters of intensity and thematic content exert separate-and in some cases interactive-modulatory effects on physiological reactions to emotional pictures.
ARTICLE UPDATE - Flanker effects with faces may depend on perceptual as well as emotional differences.
Horstmann G, Borgstedt K, Heumann M.
Emotion, 6, 28-39
Do threatening or negative faces capture attention? The authors argue that evidence from visual search, spatial cuing, and flanker tasks is equivocal and that perceptual differences may account for effects attributed to emotional categories. Empirically, the authors examine the flanker task. Although they replicate previous results in which a positive face flanked by negative faces suffers more interference than a negative face flanked by positive faces, further results indicate that face perception is not necessary for the flanker-effect asymmetry and that the asymmetry also occurs with nonemotional stimuli. The authors conclude that the flanker-effect asymmetry with affective faces cannot be unambiguously attributed to emotional differences and may well be due to purely perceptual differences between the stimuli.
Emotion, 6, 28-39
Do threatening or negative faces capture attention? The authors argue that evidence from visual search, spatial cuing, and flanker tasks is equivocal and that perceptual differences may account for effects attributed to emotional categories. Empirically, the authors examine the flanker task. Although they replicate previous results in which a positive face flanked by negative faces suffers more interference than a negative face flanked by positive faces, further results indicate that face perception is not necessary for the flanker-effect asymmetry and that the asymmetry also occurs with nonemotional stimuli. The authors conclude that the flanker-effect asymmetry with affective faces cannot be unambiguously attributed to emotional differences and may well be due to purely perceptual differences between the stimuli.
ARTICLE UPDATE - Anxiety meets fear in perception of dynamic expressive gaze.
Putman P, Hermans E, van Honk J.
Emotion, 6, 94-102
This study investigated in 2 experiments whether reflexive cuing of attention that occurs after perception of a gaze cue is greater for fearful than for happy faces in normal participants, as hypothesized from a social neuroscience perspective. To increase neuroecological validity, dynamic stimulus presentation was used to display faces that simultaneously morphed from a neutral expression into a happy or fearful one and shifted eye gaze from the center to the periphery. Shifts of attention resulting from a natural fearful gaze were expected to be related to participants' anxiety traits, in agreement with the often found increased selective attention to threat in anxious participants. Both hypotheses were confirmed: Fearful faces induced stronger gaze cuing than happy faces, and the strength of this cuing effect was correlated to participants' anxiety levels. These results suggest a neural network, which integrates the processing of gaze, expression, and emotional states to adaptively prime vigilance under threatening circumstances.
Emotion, 6, 94-102
This study investigated in 2 experiments whether reflexive cuing of attention that occurs after perception of a gaze cue is greater for fearful than for happy faces in normal participants, as hypothesized from a social neuroscience perspective. To increase neuroecological validity, dynamic stimulus presentation was used to display faces that simultaneously morphed from a neutral expression into a happy or fearful one and shifted eye gaze from the center to the periphery. Shifts of attention resulting from a natural fearful gaze were expected to be related to participants' anxiety traits, in agreement with the often found increased selective attention to threat in anxious participants. Both hypotheses were confirmed: Fearful faces induced stronger gaze cuing than happy faces, and the strength of this cuing effect was correlated to participants' anxiety levels. These results suggest a neural network, which integrates the processing of gaze, expression, and emotional states to adaptively prime vigilance under threatening circumstances.
ARTICLE UPDATE - Anxiety selectively disrupts visuospatial working memory.
Shackman AJ, Sarinopoulos I, Maxwell JS, Pizzagalli DA, Lavric A, Davidson RJ.
Emotion, 6, 40-61
On the basis of a review of the extant literature describing emotion-cognition interactions, the authors propose 4 methodological desiderata for studying how task-irrelevant affect modulates cognition and present data from an experiment satisfying them. Consistent with accounts of the hemispheric asymmetries characterizing withdrawal-related negative affect and visuospatial working memory (WM) in prefrontal and parietal cortices, threat-induced anxiety selectively disrupted accuracy of spatial but not verbal WM performance. Furthermore, individual differences in physiological measures of anxiety statistically mediated the degree of disruption. A second experiment revealed that individuals characterized by high levels of behavioral inhibition exhibited more intense anxiety and relatively worse spatial WM performance in the absence of threat, solidifying the authors' inference that anxiety causally mediates disruption. These observations suggest a revision of extant models of how anxiety sculpts cognition and underscore the utility of the desiderata.
Emotion, 6, 40-61
On the basis of a review of the extant literature describing emotion-cognition interactions, the authors propose 4 methodological desiderata for studying how task-irrelevant affect modulates cognition and present data from an experiment satisfying them. Consistent with accounts of the hemispheric asymmetries characterizing withdrawal-related negative affect and visuospatial working memory (WM) in prefrontal and parietal cortices, threat-induced anxiety selectively disrupted accuracy of spatial but not verbal WM performance. Furthermore, individual differences in physiological measures of anxiety statistically mediated the degree of disruption. A second experiment revealed that individuals characterized by high levels of behavioral inhibition exhibited more intense anxiety and relatively worse spatial WM performance in the absence of threat, solidifying the authors' inference that anxiety causally mediates disruption. These observations suggest a revision of extant models of how anxiety sculpts cognition and underscore the utility of the desiderata.
ARTICLE UPDATE - Lexical characteristics of words used in emotional Stroop experiments.
Larsen RJ, Mercer KA, Balota DA.
Emotion, 6, 62-72.
Validity of the emotional Stroop task hinges on equivalence between the emotion and the control words in terms of lexical features related to word recognition. The authors evaluated the lexical features of 1,033 words used in 32 published emotional Stroop studies. Emotion words were significantly lower in frequency of use, longer in length, and had smaller orthographic neighborhoods than words used as controls. These lexical features contribute to slower word recognition and hence are likely to contribute to delayed latencies in color naming. The often-replicated slowdown in color naming of emotion words may be due, in part, to lexical differences between the emotion and control words used in the majority of such studies to date.
Emotion, 6, 62-72.
Validity of the emotional Stroop task hinges on equivalence between the emotion and the control words in terms of lexical features related to word recognition. The authors evaluated the lexical features of 1,033 words used in 32 published emotional Stroop studies. Emotion words were significantly lower in frequency of use, longer in length, and had smaller orthographic neighborhoods than words used as controls. These lexical features contribute to slower word recognition and hence are likely to contribute to delayed latencies in color naming. The often-replicated slowdown in color naming of emotion words may be due, in part, to lexical differences between the emotion and control words used in the majority of such studies to date.
ARTICLE UPDATE - The impact of affect and frequency on lexical decision: The role of the amygdala and inferior frontal cortex.
Nakic M, Smith BW, Busis S, Vythilingam M, Blair RJ.
NeuroImage, in press
The current study used event-related fMRI to examine BOLD responses associated with two factors that behaviorally determine speed of lexical decision: frequency and emotion. Thirteen healthy adults performed a visual lexical decision task, discriminating between words and orthographically and phonologically legal nonwords. The study involved a 2 (Frequency: high and low) x 3 (Emotional arousal: highly negative, mildly negative, and neutral words) design with word categories matched for number of letters and concreteness. There were significant main effects for both frequency and emotion in lexical decision reaction times but no significant interaction. Negative word lexical decisions were associated with increased activation in bilateral amygdala and middle temporal cortex as well as rostral anterior and posterior cingulate cortex. Low-frequency word lexical decisions, relative to high-frequency word lexical decisions, were associated with increased bilateral activity in inferior frontal cortex. Inferior frontal cortex activation was particularly low during lexical decision for high-frequency emotional words but significant for high-frequency neutral emotional words. We suggest that this is because the semantic representation of high-frequency emotional words may receive sufficient additional augmentation via the reciprocal activation from the amygdala such that selective augmentation by inferior frontal cortex to achieve lexical decision is unnecessary.
NeuroImage, in press
The current study used event-related fMRI to examine BOLD responses associated with two factors that behaviorally determine speed of lexical decision: frequency and emotion. Thirteen healthy adults performed a visual lexical decision task, discriminating between words and orthographically and phonologically legal nonwords. The study involved a 2 (Frequency: high and low) x 3 (Emotional arousal: highly negative, mildly negative, and neutral words) design with word categories matched for number of letters and concreteness. There were significant main effects for both frequency and emotion in lexical decision reaction times but no significant interaction. Negative word lexical decisions were associated with increased activation in bilateral amygdala and middle temporal cortex as well as rostral anterior and posterior cingulate cortex. Low-frequency word lexical decisions, relative to high-frequency word lexical decisions, were associated with increased bilateral activity in inferior frontal cortex. Inferior frontal cortex activation was particularly low during lexical decision for high-frequency emotional words but significant for high-frequency neutral emotional words. We suggest that this is because the semantic representation of high-frequency emotional words may receive sufficient additional augmentation via the reciprocal activation from the amygdala such that selective augmentation by inferior frontal cortex to achieve lexical decision is unnecessary.
Friday, April 28, 2006
ARTICLE UPDATE - The beneficial effects of additional task load, positive affect, and instruction on the attentional blink.
Olivers CN, Nieuwenhuis S.
Journal of Experimental Psychology: Human Perception & Performances, 32, 364-379
The attentional blink reflects the impaired ability to identify the 2nd of 2 targets presented in close succession--a phenomenon that is generally thought to reflect a fundamental cognitive limitation. However, the fundamental nature of this impairment has recently been called into question by the counterintuitive finding that task-irrelevant mental activity improves attentional blink performance (C. N. L. Olivers & S. Nieuwenhuis, 2005). The present study found a reduced attentional blink when participants concurrently performed an additional memory task, viewed pictures of positive affective content, or were instructed to focus less on the task. These findings support the hypothesis that the attentional blink is due to an overinvestment of attentional resources in stimulus processing, a suboptimal processing mode that can be counteracted by manipulations promoting divided attention.
*Note that their results published in 2005 has been questioned
Journal of Experimental Psychology: Human Perception & Performances, 32, 364-379
The attentional blink reflects the impaired ability to identify the 2nd of 2 targets presented in close succession--a phenomenon that is generally thought to reflect a fundamental cognitive limitation. However, the fundamental nature of this impairment has recently been called into question by the counterintuitive finding that task-irrelevant mental activity improves attentional blink performance (C. N. L. Olivers & S. Nieuwenhuis, 2005). The present study found a reduced attentional blink when participants concurrently performed an additional memory task, viewed pictures of positive affective content, or were instructed to focus less on the task. These findings support the hypothesis that the attentional blink is due to an overinvestment of attentional resources in stimulus processing, a suboptimal processing mode that can be counteracted by manipulations promoting divided attention.
*Note that their results published in 2005 has been questioned
ARTICLE UPDATE - The impact of emotion on perception: bias or enhanced processing?
Zeelenberg R, Wagenmakers EJ, Rotteveel M.
Psychological Science, 17, 287-291
Recent studies have shown that emotionally significant stimuli are often better identified than neutral stimuli. It is not clear, however, whether these results are due to enhanced perceptual processing or to a bias favoring the identification of emotionally significant stimuli over neutral stimuli. The present study used a two-alternative forced-choice perceptual identification task to disentangle the effects of bias and enhanced processing. We found that emotionally significant targets were better identified than neutral targets. In contrast, the emotional significance of the foil alternative had no effect on performance. The present results support the hypothesis that perceptual encoding of emotionally significant stimuli is enhanced.
Psychological Science, 17, 287-291
Recent studies have shown that emotionally significant stimuli are often better identified than neutral stimuli. It is not clear, however, whether these results are due to enhanced perceptual processing or to a bias favoring the identification of emotionally significant stimuli over neutral stimuli. The present study used a two-alternative forced-choice perceptual identification task to disentangle the effects of bias and enhanced processing. We found that emotionally significant targets were better identified than neutral targets. In contrast, the emotional significance of the foil alternative had no effect on performance. The present results support the hypothesis that perceptual encoding of emotionally significant stimuli is enhanced.
ARTICLE UPDATE - Emotion facilitates perception and potentiates the perceptual benefits of attention.
Phelps EA, Ling S, Carrasco M.
Psychological Science, 17, 292-299.
Does emotion affect how people see? We investigated the effects of emotion and attention, as well as their conjoint effect, on contrast sensitivity, a dimension of early vision. We manipulated the emotional valence and the attentional distribution of cues preceding a target stimulus and asked observers to judge the orientation of the target as contrast varied. This study provides the first behavioral evidence that (a) emotion enhances contrast sensitivity irrespective of attention and (b) emotion potentiates the effect of attention on contrast sensitivity.
Psychological Science, 17, 292-299.
Does emotion affect how people see? We investigated the effects of emotion and attention, as well as their conjoint effect, on contrast sensitivity, a dimension of early vision. We manipulated the emotional valence and the attentional distribution of cues preceding a target stimulus and asked observers to judge the orientation of the target as contrast varied. This study provides the first behavioral evidence that (a) emotion enhances contrast sensitivity irrespective of attention and (b) emotion potentiates the effect of attention on contrast sensitivity.
ARTICLE UPDATE - Emotional category data on images from the International Affective Picture System.
Mikels JA, Fredrickson BL, Larkin GR, Lindberg CM, Maglio SJ, Reuter-Lorenz PA.
Behavioural Research Methods, 37, 626-630
The International Affective Picture System (IAPS) is widely used in studies of emotion and has been characterized primarily along the dimensions of valence, arousal, and dominance. Even though research has shown that the IAPS is useful in the study of discrete emotions, the categorical structure of the IAPS has not been characterized thoroughly. The purpose of the present project was to collect descriptive emotional category data on subsets of the LAPS in an effort to identify images that elicit onediscrete emotion more than others. These data reveal multiple emotional categories for the images and indicate that this image set has great potential in the investigation of discrete emotions. This article makes these data available to researchers with such interests. Data for all the pictures are archived at www.psychonomic.org/archive/. (not available on line yet)
Behavioural Research Methods, 37, 626-630
The International Affective Picture System (IAPS) is widely used in studies of emotion and has been characterized primarily along the dimensions of valence, arousal, and dominance. Even though research has shown that the IAPS is useful in the study of discrete emotions, the categorical structure of the IAPS has not been characterized thoroughly. The purpose of the present project was to collect descriptive emotional category data on subsets of the LAPS in an effort to identify images that elicit onediscrete emotion more than others. These data reveal multiple emotional categories for the images and indicate that this image set has great potential in the investigation of discrete emotions. This article makes these data available to researchers with such interests. Data for all the pictures are archived at www.psychonomic.org/archive/. (not available on line yet)
Monday, April 24, 2006
ARTICLE UPDATE - Attention does not modulate neural responses to social stimuli in autism spectrum disorders
Geoffrey Bird, Caroline Catmur, Giorgia Silani, Chris Frith and Uta Frith
NeuroImage, in press
We investigated whether individuals with autism spectrum disorders (ASD) would show attentional modulation for social (face) and non-social (house) stimuli. Sixteen individuals with ASD and 16 matched control participants completed a task in which pairs of face and house stimuli were present on every trial, with one of the pairs randomly assigned to attended locations and the other to unattended locations. Both mass-univariate (SPM) and region of interest analyses suggested that responses to houses were modulated by attention in both groups, but that only the control participants demonstrated attentional modulation of face-selective regions. Thus, the participants with ASD demonstrated a lack of attentional modulation which was particularly evident for the social stimulus. Analyses of effective connectivity indicated that these results were due to a failure of attention to modulate connectivity between extrastriate areas and V1. We discuss how these results may suggest a mechanism to explain the reduced salience of social stimuli in ASD.
NeuroImage, in press
We investigated whether individuals with autism spectrum disorders (ASD) would show attentional modulation for social (face) and non-social (house) stimuli. Sixteen individuals with ASD and 16 matched control participants completed a task in which pairs of face and house stimuli were present on every trial, with one of the pairs randomly assigned to attended locations and the other to unattended locations. Both mass-univariate (SPM) and region of interest analyses suggested that responses to houses were modulated by attention in both groups, but that only the control participants demonstrated attentional modulation of face-selective regions. Thus, the participants with ASD demonstrated a lack of attentional modulation which was particularly evident for the social stimulus. Analyses of effective connectivity indicated that these results were due to a failure of attention to modulate connectivity between extrastriate areas and V1. We discuss how these results may suggest a mechanism to explain the reduced salience of social stimuli in ASD.
Thursday, April 20, 2006
ARTICLE UPDATE - Non-conscious recognition of emotional body language.
de Gelder B, Hadjikhani N.
Neuroreport, 17, 583-586
Patients with cortical blindness can reliably perceive some facial expressions even if they are unaware of their percept. We examined whether emotional body language may also be recognized in the absence of the primary visual cortex and without conscious stimulus perception. We presented emotional and neutral body images in the blind field of a patient with unilateral striate cortex damage. Using functional magnetic resonance imaging, we measured activation following presentation to the blind hemifield of whole body images (happy, neutral) with the face blurred. Unseen happy body images selectively activated area MT and the pulvinar nucleus of the thalamus, while unseen instrumental neutral body images activated the premotor cortex. Our results show that in the absence of the striate cortex implicit bodily emotion perception may be possible.
Neuroreport, 17, 583-586
Patients with cortical blindness can reliably perceive some facial expressions even if they are unaware of their percept. We examined whether emotional body language may also be recognized in the absence of the primary visual cortex and without conscious stimulus perception. We presented emotional and neutral body images in the blind field of a patient with unilateral striate cortex damage. Using functional magnetic resonance imaging, we measured activation following presentation to the blind hemifield of whole body images (happy, neutral) with the face blurred. Unseen happy body images selectively activated area MT and the pulvinar nucleus of the thalamus, while unseen instrumental neutral body images activated the premotor cortex. Our results show that in the absence of the striate cortex implicit bodily emotion perception may be possible.
ARTICLE UPDATE - Emotional information processing in mood disorders: a review of behavioral and neuroimaging findings.
Leppanen JM.
Current Opinions in Psychiatry, 19, 34-39.
A relatively long history of research has shown that mood disorders are associated with abnormalities in the processing of emotional stimuli. Only the most recent studies, however, have begun to elucidate the specificity and neural basis of these abnormalities. This article reviews and discusses the results of these studies. RECENT FINDINGS: Individuals diagnosed with major depressive disorder exhibit an attentional bias toward negative emotional cues (e.g. sad faces), an attentional bias away from positive emotional cues (e.g. happy faces), and an enhanced memory for negative emotional material. Compared with healthy controls, individuals with major depressive disorder show increased neural activity in response to sad faces and diminished neural activity in response to happy faces in emotion-related brain circuits (e.g. amygdala and ventral striatum). Some of these abnormalities in the processing of emotional information persist after symptom remission and they have also been found in healthy individuals who are at heightened risk for the development of mood disorders. SUMMARY: The reviewed data show that major depressive disorder involves specific abnormalities in the cognitive and neural processing of emotional information and that these abnormalities may potentially contribute to the vulnerability for negative emotion and onset of depressive episodes.
Current Opinions in Psychiatry, 19, 34-39.
A relatively long history of research has shown that mood disorders are associated with abnormalities in the processing of emotional stimuli. Only the most recent studies, however, have begun to elucidate the specificity and neural basis of these abnormalities. This article reviews and discusses the results of these studies. RECENT FINDINGS: Individuals diagnosed with major depressive disorder exhibit an attentional bias toward negative emotional cues (e.g. sad faces), an attentional bias away from positive emotional cues (e.g. happy faces), and an enhanced memory for negative emotional material. Compared with healthy controls, individuals with major depressive disorder show increased neural activity in response to sad faces and diminished neural activity in response to happy faces in emotion-related brain circuits (e.g. amygdala and ventral striatum). Some of these abnormalities in the processing of emotional information persist after symptom remission and they have also been found in healthy individuals who are at heightened risk for the development of mood disorders. SUMMARY: The reviewed data show that major depressive disorder involves specific abnormalities in the cognitive and neural processing of emotional information and that these abnormalities may potentially contribute to the vulnerability for negative emotion and onset of depressive episodes.
Monday, April 03, 2006
ARTICLE UPDATE - They know the words, but not the music: Affective and semantic priming in individuals with psychopathy.
Blair KS, Richell RA, Mitchell DG, Leonard A, Morton J, Blair RJ.
Biological Psychology, in press
Previous work has indicated dysfunctional affect-language interactions in individuals with psychopathy through use of the lexical decision task. However, it has been uncertain as to whether these deficits actually reflect impaired affect-language interactions or a more fundamental deficit in general semantic processing. In this study, we examined affective priming and semantic priming (dependent measures were reaction times and error rates) in individuals with psychopathy and comparison individuals, classified according to the psychopathy checklist revised (PCL-R) [Hare, R.D., 1991. The Hare Psychopathy Checklist-Revised. Multi-Health Systems, Toronto, Ont.]. Individuals with psychopathy showed significantly less affective priming relative to comparison individuals. In contrast, the two groups showed comparable levels of semantic priming. The results are discussed with reference to current models of psychopathy.
Biological Psychology, in press
Previous work has indicated dysfunctional affect-language interactions in individuals with psychopathy through use of the lexical decision task. However, it has been uncertain as to whether these deficits actually reflect impaired affect-language interactions or a more fundamental deficit in general semantic processing. In this study, we examined affective priming and semantic priming (dependent measures were reaction times and error rates) in individuals with psychopathy and comparison individuals, classified according to the psychopathy checklist revised (PCL-R) [Hare, R.D., 1991. The Hare Psychopathy Checklist-Revised. Multi-Health Systems, Toronto, Ont.]. Individuals with psychopathy showed significantly less affective priming relative to comparison individuals. In contrast, the two groups showed comparable levels of semantic priming. The results are discussed with reference to current models of psychopathy.
ARTICLE UPDATE- Increased positive emotional memory after repetitive transcranial magnetic stimulation over the orbitofrontal cortex
Schutter DJ, van Honk J.
Journal of Psychiatry Neuroscience, 31, 101-104.
Several studies have demonstrated increased left orbitofrontal cortex (OFC) activity during negative and depressed mood. These mood states have also been associated with reduced memory for positive emotional stimuli. The aim of the present study was to investigate whether slow, inhibitory repetitive transcranial magnetic stimulation (rTMS) over the left OFC would improve memory for positive material. METHODS: We carried out a study with a double-blind, within-subjects design, in which 12 healthy volunteers received 20 minutes of slow rTMS over the left OFC, placebo treatment over the left OFC and rTMS over the left dorsolateral portion of the prefrontal cortex. Effects on memory for fearful and happy faces were investigated. RESULTS: Memory for happy faces was significantly improved after rTMS over the left OFC compared with placebo (t(10) = 2.4, p = 0.037). CONCLUSIONS: These findings suggest a role of the OFC in positive emotional memory, which is in accordance with neuroimaging and neuropsychological data. It may be argued that dense projections from the OFC to the limbic emotional circuit are involved in emotional memory and, therefore, play a role in the effects of rTMS that we observed.
Journal of Psychiatry Neuroscience, 31, 101-104.
Several studies have demonstrated increased left orbitofrontal cortex (OFC) activity during negative and depressed mood. These mood states have also been associated with reduced memory for positive emotional stimuli. The aim of the present study was to investigate whether slow, inhibitory repetitive transcranial magnetic stimulation (rTMS) over the left OFC would improve memory for positive material. METHODS: We carried out a study with a double-blind, within-subjects design, in which 12 healthy volunteers received 20 minutes of slow rTMS over the left OFC, placebo treatment over the left OFC and rTMS over the left dorsolateral portion of the prefrontal cortex. Effects on memory for fearful and happy faces were investigated. RESULTS: Memory for happy faces was significantly improved after rTMS over the left OFC compared with placebo (t(10) = 2.4, p = 0.037). CONCLUSIONS: These findings suggest a role of the OFC in positive emotional memory, which is in accordance with neuroimaging and neuropsychological data. It may be argued that dense projections from the OFC to the limbic emotional circuit are involved in emotional memory and, therefore, play a role in the effects of rTMS that we observed.
Friday, March 10, 2006
ARTICLE UPDATE - Compensatory strategies in processing facial emotions: Evidence from prosopagnosia.
Baudouin JY, Humphreys GW.
Neuropsychologica, in press
We report data on the processing of facial emotion in a prosopagnosic patient (H.J.A.). H.J.A. was relatively accurate at discriminating happy from angry upright faces, but he performed at chance when the faces were inverted. Furthermore, with upright faces there was no configural interference effect on emotion judgements, when face parts expressing different emotions were aligned to express a new emergent emotion. We propose that H.J.A.'s emotion judgements relied on local rather than on configural information, and this local information was disrupted by inversion. A compensatory strategy, based on processing local face parts, can be sufficient to process at least some facial emotions.
Neuropsychologica, in press
We report data on the processing of facial emotion in a prosopagnosic patient (H.J.A.). H.J.A. was relatively accurate at discriminating happy from angry upright faces, but he performed at chance when the faces were inverted. Furthermore, with upright faces there was no configural interference effect on emotion judgements, when face parts expressing different emotions were aligned to express a new emergent emotion. We propose that H.J.A.'s emotion judgements relied on local rather than on configural information, and this local information was disrupted by inversion. A compensatory strategy, based on processing local face parts, can be sufficient to process at least some facial emotions.
ARTICLE UPDATE - Stimulus novelty and emotion perception: the near absence of habituation in the visual cortex
Schupp HT, Stockburger J, Codispoti M, Junghofer M, Weike AI, Hamm AO.
Neuroreport, 17, 365-369
In rapid serial visual presentation of pictures, an early event-related brain potential component shows enlarged negativity over occipital regions for emotional pictures compared with neutral pictures. The present study examined whether the processing of emotional target pictures varies as a function of stimulus repetition. Accordingly, pictures of erotica, neutral contents, and mutilations were repeatedly presented (90 times) while the electroencephalogram was recorded with a 129 dense sensor array. As in previous studies, emotional pictures were associated with a larger posterior negativity than neutral pictures. Furthermore, differential emotion processing did not vary as a function of stimulus repetition and was similarly expressed across blocks of picture presentation. These findings suggest the near absence of habituation in differential emotion processing during perceptual processing.
Neuroreport, 17, 365-369
In rapid serial visual presentation of pictures, an early event-related brain potential component shows enlarged negativity over occipital regions for emotional pictures compared with neutral pictures. The present study examined whether the processing of emotional target pictures varies as a function of stimulus repetition. Accordingly, pictures of erotica, neutral contents, and mutilations were repeatedly presented (90 times) while the electroencephalogram was recorded with a 129 dense sensor array. As in previous studies, emotional pictures were associated with a larger posterior negativity than neutral pictures. Furthermore, differential emotion processing did not vary as a function of stimulus repetition and was similarly expressed across blocks of picture presentation. These findings suggest the near absence of habituation in differential emotion processing during perceptual processing.
Friday, March 03, 2006
ARTICLE UPDATE - Between-subject transfer of emotional information evokes specific pattern of amygdala activation.
Knapska E, Nikolaev E, Boguszewski P, Walasek G, Blaszczyk J, Kaczmarek L, Werka T.
PNAS, 103, 3859-3864
Emotional states displayed by an animal or a human can seriously affect behavior of their conspecifics. The amygdala plays a crucial role in the processing of emotions. In this study, we describe an experimental rat model of between-subject transfer of emotional information and its effects on activation of the amygdala. The rats were kept in pairs, and one animal (designated as "demonstrator") was treated to specific behavioral training of either foot-shock-reinforced context conditioning or just exposure to a novel context. We next examined the influence of the demonstrators on the exploratory behavior of their cagemates (called "observers") and the observers' performance of the acoustic startle response. We report that we can distinguish both groups of observers from the control animals (as shown by startle-response measure) and distinguish between observers (by means of indexing the exploration), with respect to whether they were paired with demonstrators treated to different experimental conditions. Furthermore, we show that the observers have most of their amygdala activated (as revealed by c-Fos mapping) to the same level as the demonstrators and, in the case of the central amygdala, to an even higher level. Moreover, the level of c-Fos expression in the observers reflected the specific behavioral treatment of the demonstrators with whom they were paired. Thus, in this study, we have shown that undefined emotional information transferred by a cohabitant rat can be evaluated and measured and that it evokes very strong and information-specific activation of the amygdala.
PNAS, 103, 3859-3864
Emotional states displayed by an animal or a human can seriously affect behavior of their conspecifics. The amygdala plays a crucial role in the processing of emotions. In this study, we describe an experimental rat model of between-subject transfer of emotional information and its effects on activation of the amygdala. The rats were kept in pairs, and one animal (designated as "demonstrator") was treated to specific behavioral training of either foot-shock-reinforced context conditioning or just exposure to a novel context. We next examined the influence of the demonstrators on the exploratory behavior of their cagemates (called "observers") and the observers' performance of the acoustic startle response. We report that we can distinguish both groups of observers from the control animals (as shown by startle-response measure) and distinguish between observers (by means of indexing the exploration), with respect to whether they were paired with demonstrators treated to different experimental conditions. Furthermore, we show that the observers have most of their amygdala activated (as revealed by c-Fos mapping) to the same level as the demonstrators and, in the case of the central amygdala, to an even higher level. Moreover, the level of c-Fos expression in the observers reflected the specific behavioral treatment of the demonstrators with whom they were paired. Thus, in this study, we have shown that undefined emotional information transferred by a cohabitant rat can be evaluated and measured and that it evokes very strong and information-specific activation of the amygdala.
ARTICLE UPDATE - Anxiety and sensitivity to eye gaze in emotional faces.
Holmes A, Richards A, Green S.
Brain & Cognition, 60, 282-294
This paper reports three studies in which stronger orienting to perceived eye gaze direction was revealed when observers viewed faces showing fearful or angry, compared with happy or neutral, emotional expressions. Gaze-related spatial cueing effects to laterally presented fearful faces and centrally presented angry faces were also modulated by the anxiety level of participants, with high- but not low-state anxious individuals revealing enhanced shifts of attention. In contrast, both high- and low-state anxious individuals demonstrated enhanced orienting to averted gaze when viewing laterally presented angry faces. These results provide novel evidence for the rapid integration of facial expression and gaze direction information, and for the regulation of gaze-cued attention by both the emotion conveyed in the perceived face and the degree of anxiety experienced by the observer.
Brain & Cognition, 60, 282-294
This paper reports three studies in which stronger orienting to perceived eye gaze direction was revealed when observers viewed faces showing fearful or angry, compared with happy or neutral, emotional expressions. Gaze-related spatial cueing effects to laterally presented fearful faces and centrally presented angry faces were also modulated by the anxiety level of participants, with high- but not low-state anxious individuals revealing enhanced shifts of attention. In contrast, both high- and low-state anxious individuals demonstrated enhanced orienting to averted gaze when viewing laterally presented angry faces. These results provide novel evidence for the rapid integration of facial expression and gaze direction information, and for the regulation of gaze-cued attention by both the emotion conveyed in the perceived face and the degree of anxiety experienced by the observer.
Thursday, March 02, 2006
ARTICLE UPDATE - Amygdala Activity Is Associated with the Successful Encoding of Item, But Not Source, Information for Positive and Negative Stimuli
Elizabeth A. Kensinger and Daniel L. Schacter
The Journal of Neuroscience, 26, 2564-2570
It has been debated whether the link between amygdala activity and subsequent memory is equally strong for positive and negative information. Moreover, it has been unclear whether amygdala activity at encoding corresponds with enhanced memory for all contextual aspects of the presentation of an emotional item, or whether amygdala activity primarily enhances memory for the emotional item itself. In the present functional magnetic resonance imaging study, participants encoded positive and negative stimuli while performing one of two tasks (judgment of animacy or commonness). Amygdala activity at encoding was related to subsequent memory for the positive and negative items but not to subsequent memory for the task performed. Amygdala activity showed no relationship to subsequent-memory performance for the neutral items. Regardless of the emotional content of the items, activity in the entorhinal cortex corresponded with subsequent memory for the item but not with memory for the task performed, whereas hippocampal activity corresponded with subsequent memory for the task performed. These results are the first to demonstrate that the amygdala can be equally engaged during the successful encoding of positive and negative items but that its activity does not facilitate the encoding of all contextual elements present during an encoding episode. The results further suggest that dissociations within the medial temporal lobe sometimes noted for nonemotional information (i.e., activity in the hippocampus proper leading to later memory for context, and activity in the entorhinal cortex leading to later memory for an item but not its context) also hold for emotional information.
The Journal of Neuroscience, 26, 2564-2570
It has been debated whether the link between amygdala activity and subsequent memory is equally strong for positive and negative information. Moreover, it has been unclear whether amygdala activity at encoding corresponds with enhanced memory for all contextual aspects of the presentation of an emotional item, or whether amygdala activity primarily enhances memory for the emotional item itself. In the present functional magnetic resonance imaging study, participants encoded positive and negative stimuli while performing one of two tasks (judgment of animacy or commonness). Amygdala activity at encoding was related to subsequent memory for the positive and negative items but not to subsequent memory for the task performed. Amygdala activity showed no relationship to subsequent-memory performance for the neutral items. Regardless of the emotional content of the items, activity in the entorhinal cortex corresponded with subsequent memory for the item but not with memory for the task performed, whereas hippocampal activity corresponded with subsequent memory for the task performed. These results are the first to demonstrate that the amygdala can be equally engaged during the successful encoding of positive and negative items but that its activity does not facilitate the encoding of all contextual elements present during an encoding episode. The results further suggest that dissociations within the medial temporal lobe sometimes noted for nonemotional information (i.e., activity in the hippocampus proper leading to later memory for context, and activity in the entorhinal cortex leading to later memory for an item but not its context) also hold for emotional information.
Friday, February 24, 2006
ARTICLE UPDATE - Towards the neurobiology of emotional body language
de Gelder B.
Nature Review Neuroscience, 7, 242-249
People's faces show fear in many different circumstances. However, when people are terrified, as well as showing emotion, they run for cover. When we see a bodily expression of emotion, we immediately know what specific action is associated with a particular emotion, leaving little need for interpretation of the signal, as is the case for facial expressions. Research on emotional body language is rapidly emerging as a new field in cognitive and affective neuroscience. This article reviews how whole-body signals are automatically perceived and understood, and their role in emotional communication and decision-making.
Nature Review Neuroscience, 7, 242-249
People's faces show fear in many different circumstances. However, when people are terrified, as well as showing emotion, they run for cover. When we see a bodily expression of emotion, we immediately know what specific action is associated with a particular emotion, leaving little need for interpretation of the signal, as is the case for facial expressions. Research on emotional body language is rapidly emerging as a new field in cognitive and affective neuroscience. This article reviews how whole-body signals are automatically perceived and understood, and their role in emotional communication and decision-making.
ARTICLE UPDATE - Attentional modulation of the amygdala varies with personality
Steven B. Most, Marvin M. Chun, Matthew R. Johnson and Kent A. Kiehl
NeuroImage, in press
The amygdala is implicated in emotional processing, and its rich subcortical connections have led to suggestions that processing of emotional stimuli occurs independently of attention. Using a novel attentional manipulation in conjunction with fMRI, we showed that emotion-related amygdala activity was modulated by attention, but that the degree of such modulation correlated with the personality variable harm avoidance, associated with trait anxiety. Participants ignored emotional distractors while searching through a rapid stream of pictures for a target, about which they were provided either specific or nonspecific descriptive information (e.g., “look for a building” versus “look for a landscape or building”). Thus, they employed either a specific or a nonspecific attentional set in order to find the target and ignore distractors. In response to irrelevant emotional distractors, low harm-avoidant participants had relatively little emotion-related amygdala activity regardless of whether they maintained a specific or nonspecific attentional set. High harm-avoidant participants, however, showed strong emotion-related amygdala activity when maintaining a nonspecific attentional set and lower amygdala activity when maintaining a specific attentional set. This decrease was accompanied by increased activation of the rostral anterior cingulate cortex (ACC), which is often linked with the resolution of affective interference. In addition to demonstrating individual differences in attentional modulation of the amygdala, these results may indicate that the rostral ACC is sensitive to the increased effort that high harm-avoidant individuals must recruit in order to modulate amygdala responsivity.
NeuroImage, in press
The amygdala is implicated in emotional processing, and its rich subcortical connections have led to suggestions that processing of emotional stimuli occurs independently of attention. Using a novel attentional manipulation in conjunction with fMRI, we showed that emotion-related amygdala activity was modulated by attention, but that the degree of such modulation correlated with the personality variable harm avoidance, associated with trait anxiety. Participants ignored emotional distractors while searching through a rapid stream of pictures for a target, about which they were provided either specific or nonspecific descriptive information (e.g., “look for a building” versus “look for a landscape or building”). Thus, they employed either a specific or a nonspecific attentional set in order to find the target and ignore distractors. In response to irrelevant emotional distractors, low harm-avoidant participants had relatively little emotion-related amygdala activity regardless of whether they maintained a specific or nonspecific attentional set. High harm-avoidant participants, however, showed strong emotion-related amygdala activity when maintaining a nonspecific attentional set and lower amygdala activity when maintaining a specific attentional set. This decrease was accompanied by increased activation of the rostral anterior cingulate cortex (ACC), which is often linked with the resolution of affective interference. In addition to demonstrating individual differences in attentional modulation of the amygdala, these results may indicate that the rostral ACC is sensitive to the increased effort that high harm-avoidant individuals must recruit in order to modulate amygdala responsivity.
Monday, February 20, 2006
ARTICLE UPDATE - Facial expressions and complex IAPS pictures: Common and differential networks
Jennifer C. Britton, Stephan F. Taylor, Keith D. Sudheimer and Israel Liberzon
NeuroImage, in press
Neuroimaging studies investigating emotion have commonly used two different visual stimulus formats, facial expressions of emotion or emotionally evocative scenes. However, it remains an important unanswered question whether or not these different stimulus formats entail the same processes. Facial expressions of emotion may elicit more emotion recognition/perception, and evocative pictures may elicit more direct experience of emotion. In spite of these differences, common areas of activation have been reported across different studies, but little work has investigated activations in response to the two stimulus formats in the same subjects. In this fMRI study, we compared BOLD activation patterns to facial expression of emotions and to complex emotional pictures from the International Affective Picture System (IAPS) to determine if these stimuli would activate similar or distinct brain regions. Healthy volunteers passively viewed blocks of expressive faces and IAPS pictures balanced for specific emotion (happy, sad, anger, fear, neutral), interleaved with blocks of fixation. Eye movement, reaction times, and off-line subjective ratings including discrete emotion, valence, and arousal were also recorded. Both faces and IAPS pictures activated similar structures, including the amygdala, posterior hippocampus, ventromedial prefrontal cortex, and visual cortex. In addition, expressive faces uniquely activated the superior temporal gyrus, insula, and anterior cingulate more than IAPS pictures, despite the faces being less arousing. For the most part, these regions were activated in response to all specific emotions; however, some regions responded only to a subset.
NeuroImage, in press
Neuroimaging studies investigating emotion have commonly used two different visual stimulus formats, facial expressions of emotion or emotionally evocative scenes. However, it remains an important unanswered question whether or not these different stimulus formats entail the same processes. Facial expressions of emotion may elicit more emotion recognition/perception, and evocative pictures may elicit more direct experience of emotion. In spite of these differences, common areas of activation have been reported across different studies, but little work has investigated activations in response to the two stimulus formats in the same subjects. In this fMRI study, we compared BOLD activation patterns to facial expression of emotions and to complex emotional pictures from the International Affective Picture System (IAPS) to determine if these stimuli would activate similar or distinct brain regions. Healthy volunteers passively viewed blocks of expressive faces and IAPS pictures balanced for specific emotion (happy, sad, anger, fear, neutral), interleaved with blocks of fixation. Eye movement, reaction times, and off-line subjective ratings including discrete emotion, valence, and arousal were also recorded. Both faces and IAPS pictures activated similar structures, including the amygdala, posterior hippocampus, ventromedial prefrontal cortex, and visual cortex. In addition, expressive faces uniquely activated the superior temporal gyrus, insula, and anterior cingulate more than IAPS pictures, despite the faces being less arousing. For the most part, these regions were activated in response to all specific emotions; however, some regions responded only to a subset.
ARTICLE UPDATE - Neural systems for orienting attention to the location of threat signals: An event-related fMRI study
Gilles Pourtois, Sophie Schwartz, Mohamed L. Seghier, François Lazeyras and Patrik Vuilleumier
NeuroImage, in press
Attention may reflexively shift towards the location of perceived threats, but it is still unclear how these spatial biases recruit the distributed fronto-parietal cortical networks involved in other aspects of selective attention. We used event-related fMRI to determine how brain responses to a neutral visual target are influenced by the emotional expression of faces appearing at the same location during a covert orienting task. On each trial, two faces were briefly presented, one in each upper visual field (one neutral and one emotional, fearful or happy), followed by a unilateral target (a small horizontal or vertical bar) replacing one of the faces. Participants had to discriminate the target orientation, shown on the same (valid) or opposite (invalid) side as the emotional face. Trials with faces but no subsequent target (cue-only trials) were included to disentangle activation due to emotional cues from their effects on target detection. We found increased responses in bilateral temporo-parietal areas and right occipito-parietal cortex for fearful faces relative to happy faces, unrelated to the subsequent target and cueing validity. More critically, we found a selective modulation of intraparietal and orbitofrontal cortex for targets following an invalid fearful face, as well as an increased visual response in right lateral occipital cortex for targets following a valid fearful face. No such effects were observed with happy faces. These results demonstrate that fearful faces can act as exogenous cues by increasing sensory processing in extrastriate cortex for a subsequent target presented at the same location, but also produce a cost in disengaging towards another location by altering the response of IPS to invalidly cued targets. Neural mechanisms responsible for orienting attention towards emotional vs. non-emotional stimuli are thus partly shared in parietal and visual areas, but also partly distinct.
NeuroImage, in press
Attention may reflexively shift towards the location of perceived threats, but it is still unclear how these spatial biases recruit the distributed fronto-parietal cortical networks involved in other aspects of selective attention. We used event-related fMRI to determine how brain responses to a neutral visual target are influenced by the emotional expression of faces appearing at the same location during a covert orienting task. On each trial, two faces were briefly presented, one in each upper visual field (one neutral and one emotional, fearful or happy), followed by a unilateral target (a small horizontal or vertical bar) replacing one of the faces. Participants had to discriminate the target orientation, shown on the same (valid) or opposite (invalid) side as the emotional face. Trials with faces but no subsequent target (cue-only trials) were included to disentangle activation due to emotional cues from their effects on target detection. We found increased responses in bilateral temporo-parietal areas and right occipito-parietal cortex for fearful faces relative to happy faces, unrelated to the subsequent target and cueing validity. More critically, we found a selective modulation of intraparietal and orbitofrontal cortex for targets following an invalid fearful face, as well as an increased visual response in right lateral occipital cortex for targets following a valid fearful face. No such effects were observed with happy faces. These results demonstrate that fearful faces can act as exogenous cues by increasing sensory processing in extrastriate cortex for a subsequent target presented at the same location, but also produce a cost in disengaging towards another location by altering the response of IPS to invalidly cued targets. Neural mechanisms responsible for orienting attention towards emotional vs. non-emotional stimuli are thus partly shared in parietal and visual areas, but also partly distinct.
Friday, February 17, 2006
ARTICLE UPDATE - Task and content modulate amygdala-hippocampal connectivity in emotional retrieval.
Smith AP, Stephan KE, Rugg MD, Dolan RJ.
Neuron, 16, 631-638.
The ability to remember emotional events is crucial for adapting to biologically and socially significant situations. Little is known, however, about the nature of the neural interactions supporting the integration of mnemonic and emotional information. Using fMRI and dynamic models of effective connectivity, we examined regional neural activity and specific interactions between brain regions during a contextual memory retrieval task. We independently manipulated emotional context and relevance of retrieved emotional information to task demands. We show that retrieval of emotionally valenced contextual information is associated with enhanced connectivity from hippocampus to amygdala, structures crucially involved with encoding of emotional events. When retrieval of emotional information is relevant to current behavior, amygdala-hippocampal connectivity increases bidirectionally, under modulatory influences from orbitofrontal cortex, a region implicated in representation of affective value and behavioral guidance. Our findings demonstrate that both memory content and behavioral context impact upon large scale neuronal dynamics underlying emotional retrieval.
Neuron, 16, 631-638.
The ability to remember emotional events is crucial for adapting to biologically and socially significant situations. Little is known, however, about the nature of the neural interactions supporting the integration of mnemonic and emotional information. Using fMRI and dynamic models of effective connectivity, we examined regional neural activity and specific interactions between brain regions during a contextual memory retrieval task. We independently manipulated emotional context and relevance of retrieved emotional information to task demands. We show that retrieval of emotionally valenced contextual information is associated with enhanced connectivity from hippocampus to amygdala, structures crucially involved with encoding of emotional events. When retrieval of emotional information is relevant to current behavior, amygdala-hippocampal connectivity increases bidirectionally, under modulatory influences from orbitofrontal cortex, a region implicated in representation of affective value and behavioral guidance. Our findings demonstrate that both memory content and behavioral context impact upon large scale neuronal dynamics underlying emotional retrieval.
ARTICLE UPDATE - Does emotion help or hinder immediate memory? Arousal versus priority-binding mechanisms.
Hadley CB, Mackay DG.
Journal of Experimental Psychology: Learning, Memory and Cognition, 32, 79-88.
People recall taboo words better than neutral words in many experimental contexts. The present rapid serial visual presentation (RSVP) experiments demonstrated this taboo-superiority effect for immediate recall of mixed lists containing taboo and neutral words matched for familiarity, length, and category coherence. Under binding theory (MacKay et al., 2004), taboo superiority reflects an interference effect: Because the emotional reaction system prioritizes binding mechanisms for linking the source of an emotion to its context, taboo words capture the mechanisms for encoding list context in mixed lists, impairing the encoding of adjacent neutral words when RSVP rates are sufficiently rapid. However, for pure or unmixed lists, binding theory predicted no better recall of taboo-only than of neutral-only lists at fast or slow rates. Present results supported this prediction, suggesting that taboo superiority in immediate recall reflects context-specific binding processes, rather than context-free arousal effects, or emotion-linked differences in rehearsal, processing time, output interference, time-based decay, or guessing biases.
Journal of Experimental Psychology: Learning, Memory and Cognition, 32, 79-88.
People recall taboo words better than neutral words in many experimental contexts. The present rapid serial visual presentation (RSVP) experiments demonstrated this taboo-superiority effect for immediate recall of mixed lists containing taboo and neutral words matched for familiarity, length, and category coherence. Under binding theory (MacKay et al., 2004), taboo superiority reflects an interference effect: Because the emotional reaction system prioritizes binding mechanisms for linking the source of an emotion to its context, taboo words capture the mechanisms for encoding list context in mixed lists, impairing the encoding of adjacent neutral words when RSVP rates are sufficiently rapid. However, for pure or unmixed lists, binding theory predicted no better recall of taboo-only than of neutral-only lists at fast or slow rates. Present results supported this prediction, suggesting that taboo superiority in immediate recall reflects context-specific binding processes, rather than context-free arousal effects, or emotion-linked differences in rehearsal, processing time, output interference, time-based decay, or guessing biases.
ARTICLE UPDATE - Affective context-induced modulation of the error-related negativity.
Larson MJ, Perlstein WM, Stigge-Kaufman D, Kelly KG, Dotson VM.
NeuroReport, 17, 329-333.
The error-related negativity putatively reflects the activity of performance-monitoring processes influenced by motivational factors, and is overactive in certain anxiety states, suggesting that affective factors affect its generation. We examined the effects of emotionally arousing and neutral task-irrelevant backgrounds on the error-related negativity to determine whether an affective context 'mismatch' alters error-related neural processing. Event-related potentials were acquired while healthy participants performed a modified Eriksen flanker task wherein flanker stimuli were superimposed on neutral, pleasant, and unpleasant pictures. The error-related negativity varied as a function of picture valence, peaking both earlier and larger in the context of pleasant backgrounds than neutral or unpleasant backgrounds. Findings support the hypothesis that affective factors influence the error-related negativity, potentially reflecting an affective mismatch associated with performance monitoring.
NeuroReport, 17, 329-333.
The error-related negativity putatively reflects the activity of performance-monitoring processes influenced by motivational factors, and is overactive in certain anxiety states, suggesting that affective factors affect its generation. We examined the effects of emotionally arousing and neutral task-irrelevant backgrounds on the error-related negativity to determine whether an affective context 'mismatch' alters error-related neural processing. Event-related potentials were acquired while healthy participants performed a modified Eriksen flanker task wherein flanker stimuli were superimposed on neutral, pleasant, and unpleasant pictures. The error-related negativity varied as a function of picture valence, peaking both earlier and larger in the context of pleasant backgrounds than neutral or unpleasant backgrounds. Findings support the hypothesis that affective factors influence the error-related negativity, potentially reflecting an affective mismatch associated with performance monitoring.
Thursday, February 16, 2006
ARTICLE UPDATE - Brain Systems Mediating Cognitive Interference by Emotional Distraction
Florin Dolcos and Gregory McCarthy
The Journal of Neuroscience, 26, 2072-2079
Flexible behavior depends on our ability to cope with distracting stimuli that can interfere with the attainment of goals. Emotional distracters can be particularly disruptive to goal-oriented behavior, but the neural systems through which these detrimental effects are mediated are not known. We used event-related functional magnetic resonance imaging to investigate the effect of emotional and nonemotional distracters on a delayed-response working memory (WM) task. As expected, this task evoked robust activity during the delay period in typical WM regions (dorsolateral prefrontal cortex and lateral parietal cortex). Presentation of emotional distracters during the delay interval evoked strong activity in typical emotional processing regions (amygdala and ventrolateral prefrontal cortex) while simultaneously evoking relative deactivation of the WM regions and impairing WM performance. These results provide the first direct evidence that the detrimental effect of emotional distracters on ongoing cognitive processes entails the interaction between a dorsal neural system associated with "cold" executive processing and a ventral system associated with "hot" emotional processing.
The Journal of Neuroscience, 26, 2072-2079
Flexible behavior depends on our ability to cope with distracting stimuli that can interfere with the attainment of goals. Emotional distracters can be particularly disruptive to goal-oriented behavior, but the neural systems through which these detrimental effects are mediated are not known. We used event-related functional magnetic resonance imaging to investigate the effect of emotional and nonemotional distracters on a delayed-response working memory (WM) task. As expected, this task evoked robust activity during the delay period in typical WM regions (dorsolateral prefrontal cortex and lateral parietal cortex). Presentation of emotional distracters during the delay interval evoked strong activity in typical emotional processing regions (amygdala and ventrolateral prefrontal cortex) while simultaneously evoking relative deactivation of the WM regions and impairing WM performance. These results provide the first direct evidence that the detrimental effect of emotional distracters on ongoing cognitive processes entails the interaction between a dorsal neural system associated with "cold" executive processing and a ventral system associated with "hot" emotional processing.
Monday, February 13, 2006
ARTICLE UPDATE - The ‘when’ anard ‘where’ of perceiving signals of threat versus non-threat
Leanne M. Williams, Donna Palmer, Belinda J. Liddell, Le Song and Evian Gordon
NeuroImage, in press
We tested the proposal that signals of potential threat are given precedence over positive and neutral signals, reflected in earlier and more pronounced changes in neural activity. The temporal sequence (‘when’) and source localization (‘where’) of event-related potentials (ERPs) elicited by fearful and happy facial expressions, compared to neutral control expressions, were examined for 219 healthy subjects. We scored ERPs over occipito-temporal sites (N80, 50–120 ms; P120, 80–180 ms; N170, 120–220 ms; P230, 180–290 ms; N250, 230–350 ms) and their polarity-reversed counterparts over medial sites (P80, 40–120 ms; N120, 80–150 ms; VPP, 120–220 ms; N200, 150–280 ms; P300, 280–450 ms). In addition to scoring peak amplitude and latency, the anatomical sources of activity were determined using low resolution brain electromagnetic tomography (LORETA). Fearful faces were distinguished by persistent increases in positivity, associated with a dynamical shift from temporo-frontal (first 120 ms) to more distributed cortical sources (120–220 ms) and back (220–450 ms). By contrast, expressions of happiness produced a discrete enhancement of negativity, later in the time course (230–350 ms) and localized to the fusiform region of the temporal cortex. In common, fear and happiness modulated the face-related N170, and produced generally greater right hemisphere activity. These findings support the proposal that fear signals are given precedence in the neural processing systems, such that processing of positive signals may be suppressed until vigilance for potential danger is completed. While fear may be processed via parallel pathways (one initiated prior to structural encoding), neural systems supporting positively valenced input may be more localized and rely on structural encoding.
NeuroImage, in press
We tested the proposal that signals of potential threat are given precedence over positive and neutral signals, reflected in earlier and more pronounced changes in neural activity. The temporal sequence (‘when’) and source localization (‘where’) of event-related potentials (ERPs) elicited by fearful and happy facial expressions, compared to neutral control expressions, were examined for 219 healthy subjects. We scored ERPs over occipito-temporal sites (N80, 50–120 ms; P120, 80–180 ms; N170, 120–220 ms; P230, 180–290 ms; N250, 230–350 ms) and their polarity-reversed counterparts over medial sites (P80, 40–120 ms; N120, 80–150 ms; VPP, 120–220 ms; N200, 150–280 ms; P300, 280–450 ms). In addition to scoring peak amplitude and latency, the anatomical sources of activity were determined using low resolution brain electromagnetic tomography (LORETA). Fearful faces were distinguished by persistent increases in positivity, associated with a dynamical shift from temporo-frontal (first 120 ms) to more distributed cortical sources (120–220 ms) and back (220–450 ms). By contrast, expressions of happiness produced a discrete enhancement of negativity, later in the time course (230–350 ms) and localized to the fusiform region of the temporal cortex. In common, fear and happiness modulated the face-related N170, and produced generally greater right hemisphere activity. These findings support the proposal that fear signals are given precedence in the neural processing systems, such that processing of positive signals may be suppressed until vigilance for potential danger is completed. While fear may be processed via parallel pathways (one initiated prior to structural encoding), neural systems supporting positively valenced input may be more localized and rely on structural encoding.
ARTICLE UPDATE - The interaction of emotional and cognitive neural systems in emotionally guided response inhibition
Keith M. Shafritz, Susan H. Collins and Hilary P. Blumberg
NeuroImage, in press
The ability to generate appropriate responses in social situations often requires the integration of emotional information conveyed through facial expressions with ongoing cognitive processes. Neuroimaging studies have begun to address how cognitive and emotional neural systems interact, but most of these studies have used emotional oddball stimuli as distractors in order to dissociate emotional from cognitive neural systems. Therefore, the manner in which these systems interact when behavioral responses must be directly guided by the emotional content of stimuli remains elusive. Here, we used functional magnetic resonance imaging (fMRI) to investigate the neural systems involved in response inhibition for faces conveying particular emotions. Participants performed go/no-go tasks involving either letters or happy and sad faces. The fMRI results indicated that inhibiting responses to emotional faces activated inferior frontal/insular cortex, whereas response inhibition during the letter task did not strongly engage this region. In addition, distinct regions of ventral anterior cingulate were preferentially activated for sad faces in the go and no-go conditions. These findings suggest that inhibition within an emotional context recruits a distinct set of brain regions that includes areas beyond those normally activated by response inhibition tasks and that can be modulated by emotional valence.
NeuroImage, in press
The ability to generate appropriate responses in social situations often requires the integration of emotional information conveyed through facial expressions with ongoing cognitive processes. Neuroimaging studies have begun to address how cognitive and emotional neural systems interact, but most of these studies have used emotional oddball stimuli as distractors in order to dissociate emotional from cognitive neural systems. Therefore, the manner in which these systems interact when behavioral responses must be directly guided by the emotional content of stimuli remains elusive. Here, we used functional magnetic resonance imaging (fMRI) to investigate the neural systems involved in response inhibition for faces conveying particular emotions. Participants performed go/no-go tasks involving either letters or happy and sad faces. The fMRI results indicated that inhibiting responses to emotional faces activated inferior frontal/insular cortex, whereas response inhibition during the letter task did not strongly engage this region. In addition, distinct regions of ventral anterior cingulate were preferentially activated for sad faces in the go and no-go conditions. These findings suggest that inhibition within an emotional context recruits a distinct set of brain regions that includes areas beyond those normally activated by response inhibition tasks and that can be modulated by emotional valence.
Friday, February 10, 2006
ARTICLE UPDATE - Anxiety modulates the degree of attentive resources required to process emotional faces
Fox, Elaine; Russo, Riccardo; Georgiou, George A.
Cognitive, Affective, & Behavioral Neuroscience, 5, 396-404
The present study contributes to the ongoing debate over the extent to which attentive resources are required for emotion perception. Although fearful facial expressions are strong competitors for attention, we predict that the magnitude of this effect may be modulated by anxiety. To test this hypothesis, healthy volunteers who varied in their self-reported levels of trait and state anxiety underwent an attentional blink task. Both fearful and happy facial expressions were subject to a strong attentional blink effect for low-anxious individuals. For those reporting high anxiety, a blink occurred for both fearful and happy facial expressions, but the magnitude of the attentional blink was significantly reduced for the fearful expressions. This supports the proposals that emotion perception is not fully automatic and that anxiety is related to a reduced ability to inhibit the processing of threat-related stimuli. Thus, individual differences in self-reported anxiety are an important determinant of the attentional control of emotional processing.
Cognitive, Affective, & Behavioral Neuroscience, 5, 396-404
The present study contributes to the ongoing debate over the extent to which attentive resources are required for emotion perception. Although fearful facial expressions are strong competitors for attention, we predict that the magnitude of this effect may be modulated by anxiety. To test this hypothesis, healthy volunteers who varied in their self-reported levels of trait and state anxiety underwent an attentional blink task. Both fearful and happy facial expressions were subject to a strong attentional blink effect for low-anxious individuals. For those reporting high anxiety, a blink occurred for both fearful and happy facial expressions, but the magnitude of the attentional blink was significantly reduced for the fearful expressions. This supports the proposals that emotion perception is not fully automatic and that anxiety is related to a reduced ability to inhibit the processing of threat-related stimuli. Thus, individual differences in self-reported anxiety are an important determinant of the attentional control of emotional processing.
ARTICLE UPDATE - The emotional power of music: How music enhances the feeling of affective pictures
Baumgartner T, Lutz K, Schmidt CF, Jancke L.
Brain Research, in press
Music is an intriguing stimulus widely used in movies to increase the emotional experience. However, no brain imaging study has to date examined this enhancement effect using emotional pictures (the modality mostly used in emotion research) and musical excerpts. Therefore, we designed this functional magnetic resonance imaging study to explore how musical stimuli enhance the feeling of affective pictures. In a classical block design carefully controlling for habituation and order effects, we presented fearful and sad pictures (mostly taken from the IAPS) either alone or combined with congruent emotional musical excerpts (classical pieces). Subjective ratings clearly indicated that the emotional experience was markedly increased in the combined relative to the picture condition. Furthermore, using a second-level analysis and regions of interest approach, we observed a clear functional and structural dissociation between the combined and the picture condition. Besides increased activation in brain areas known to be involved in auditory as well as in neutral and emotional visual-auditory integration processes, the combined condition showed increased activation in many structures known to be involved in emotion processing (including for example amygdala, hippocampus, parahippocampus, insula, striatum, medial ventral frontal cortex, cerebellum, fusiform gyrus). In contrast, the picture condition only showed an activation increase in the cognitive part of the prefrontal cortex, mainly in the right dorsolateral prefrontal cortex. Based on these findings, we suggest that emotional pictures evoke a more cognitive mode of emotion perception, whereas congruent presentations of emotional visual and musical stimuli rather automatically evoke strong emotional feelings and experiences.
Brain Research, in press
Music is an intriguing stimulus widely used in movies to increase the emotional experience. However, no brain imaging study has to date examined this enhancement effect using emotional pictures (the modality mostly used in emotion research) and musical excerpts. Therefore, we designed this functional magnetic resonance imaging study to explore how musical stimuli enhance the feeling of affective pictures. In a classical block design carefully controlling for habituation and order effects, we presented fearful and sad pictures (mostly taken from the IAPS) either alone or combined with congruent emotional musical excerpts (classical pieces). Subjective ratings clearly indicated that the emotional experience was markedly increased in the combined relative to the picture condition. Furthermore, using a second-level analysis and regions of interest approach, we observed a clear functional and structural dissociation between the combined and the picture condition. Besides increased activation in brain areas known to be involved in auditory as well as in neutral and emotional visual-auditory integration processes, the combined condition showed increased activation in many structures known to be involved in emotion processing (including for example amygdala, hippocampus, parahippocampus, insula, striatum, medial ventral frontal cortex, cerebellum, fusiform gyrus). In contrast, the picture condition only showed an activation increase in the cognitive part of the prefrontal cortex, mainly in the right dorsolateral prefrontal cortex. Based on these findings, we suggest that emotional pictures evoke a more cognitive mode of emotion perception, whereas congruent presentations of emotional visual and musical stimuli rather automatically evoke strong emotional feelings and experiences.
Friday, February 03, 2006
ARTICLE UPDATE - Temporal course of emotional negativity bias: An ERP study.
Huang YX, Luo YJ.
Neuroscience Letter, in press
There is considerable evidence that people are especially sensitive to emotionally negative materials. However, the temporal course of the negativity bias is still unclear. To address this issue, we observed the changes of P2, late positive components (LPC) and lateralized readiness potential (LRP) under positive, negative and neutral conditions, with International Affective Picture System (IAPS) pictures as emotional stimuli. We found that the amplitude of P2 in the negative block was significantly larger than that in the positive block, indicating that the attentional negativity bias occured very early in emotion perception. The LPC amplitude evoked by negative pictures was larger than that by positive and neutral pictures, suggesting that the negativity bias also occurred in a later evaluation stage of emotion processing. The response-locked LRP interval was shortest in the block of negative pictures, indicating that the negative contents elicited a reaction priming effect. Above all, this research showed that emotional negativity bias could occur in several temporal stages distinguished by attention, evaluation and reaction readiness periods.
Neuroscience Letter, in press
There is considerable evidence that people are especially sensitive to emotionally negative materials. However, the temporal course of the negativity bias is still unclear. To address this issue, we observed the changes of P2, late positive components (LPC) and lateralized readiness potential (LRP) under positive, negative and neutral conditions, with International Affective Picture System (IAPS) pictures as emotional stimuli. We found that the amplitude of P2 in the negative block was significantly larger than that in the positive block, indicating that the attentional negativity bias occured very early in emotion perception. The LPC amplitude evoked by negative pictures was larger than that by positive and neutral pictures, suggesting that the negativity bias also occurred in a later evaluation stage of emotion processing. The response-locked LRP interval was shortest in the block of negative pictures, indicating that the negative contents elicited a reaction priming effect. Above all, this research showed that emotional negativity bias could occur in several temporal stages distinguished by attention, evaluation and reaction readiness periods.
ARTICLE UPDATE - Target Visibility and Visual Awareness Modulate Amygdala Responses to Fearful Faces
Luiz Pessoa, Shruti Japee, David Sturman and Leslie G. Ungerleider
Cerebral Cortex, 16, 366-375
The goals of the present study were twofold. First, we wished to investigate the neural correlates of aware and unaware emotional face perception after characterizing each subject's behavioral performance via signal detection theory methods. Second, we wished to investigate the extent to which amygdala responses to fearful faces depend on the physical characteristics of the stimulus independently of the percept. We show that amygdala responses depend on visual awareness. Under conditions in which subjects were not aware of fearful faces flashed for 33 ms, no differential activation was observed in the amygdala. On the other hand, differential activation was observed for 67 ms fearful targets that the subjects could reliably detect. When trials were divided into hits, misses, correct rejects, and false alarms, we show that target visibility is an important factor in determining amygdala responses to fearful faces. Taken together, our results further challenge the view that amygdala responses occur automatically.
Cerebral Cortex, 16, 366-375
The goals of the present study were twofold. First, we wished to investigate the neural correlates of aware and unaware emotional face perception after characterizing each subject's behavioral performance via signal detection theory methods. Second, we wished to investigate the extent to which amygdala responses to fearful faces depend on the physical characteristics of the stimulus independently of the percept. We show that amygdala responses depend on visual awareness. Under conditions in which subjects were not aware of fearful faces flashed for 33 ms, no differential activation was observed in the amygdala. On the other hand, differential activation was observed for 67 ms fearful targets that the subjects could reliably detect. When trials were divided into hits, misses, correct rejects, and false alarms, we show that target visibility is an important factor in determining amygdala responses to fearful faces. Taken together, our results further challenge the view that amygdala responses occur automatically.
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