Smith FW, Schyns PG.
Psychological Science, in press
ABSTRACT- It is well established that animal communication signals have adapted to the evolutionary pressures of their environment. For example, the low-frequency vocalizations of the elephant are tailored to long-range communications, whereas the high-frequency trills of birds are adapted to their more localized acoustic niche. Like the voice, the human face transmits social signals about the internal emotional state of the transmitter. Here, we address two main issues: First, we characterized the spectral composition of the facial features signaling each of the six universal expressions of emotion (happiness, sadness, fear, disgust, anger, and surprise). From these analyses, we then predicted and tested the effectiveness of the transmission of emotion signals over different viewing distances. We reveal a gradient of recognition over viewing distances constraining the relative adaptive usefulness of facial expressions of emotion (distal expressions are good signals over a wide range of viewing distances; proximal expressions are suited to closer-range communication).
Monday, August 24, 2009
ARTICLE UPDATE - Response and habituation of the amygdala during processing of emotional prosody.
Wiethoff S, Wildgruber D, Grodd W, Ethofer T.
Neuroreport, in press
The role of the amygdala in processing acoustic information of affective value is still under debate. Using event-related functional MRI (fMRI), we showed increased amygdalar responses to various emotions (anger, fear, happiness, eroticism) expressed by prosody, a means of communication bound to language and consequently unique to humans. The smallest signal increases were found for fearful prosody, a finding that could not be explained by rapid response habituation to stimuli of this emotional category, challenging classical theories about fear specificity of the human amygdala. Our results converge with earlier neuroimaging evidence investigating emotional vocalizations, and these neurobiological similarities suggest that the two forms of communication might have common evolutionary roots.
Neuroreport, in press
The role of the amygdala in processing acoustic information of affective value is still under debate. Using event-related functional MRI (fMRI), we showed increased amygdalar responses to various emotions (anger, fear, happiness, eroticism) expressed by prosody, a means of communication bound to language and consequently unique to humans. The smallest signal increases were found for fearful prosody, a finding that could not be explained by rapid response habituation to stimuli of this emotional category, challenging classical theories about fear specificity of the human amygdala. Our results converge with earlier neuroimaging evidence investigating emotional vocalizations, and these neurobiological similarities suggest that the two forms of communication might have common evolutionary roots.
Monday, August 17, 2009
ARTICLE UPDATE - Distinct brain systems underlie the processing of valence and arousal of affective pictures.
Nielen MM, Heslenfeld DJ, Heinen K, Van Strien JW, Witter MP, Jonker C, Veltman DJ.
Brain & Cognition, in press
Valence and arousal are thought to be the primary dimensions of human emotion. However, the degree to which valence and arousal interact in determining brain responses to emotional pictures is still elusive. This functional MRI study aimed to delineate neural systems responding to valence and arousal, and their interaction. We measured neural activation in healthy females (N=23) to affective pictures using a 2 (Valence)x2 (Arousal) design. Results show that arousal was preferentially processed by middle temporal gyrus, hippocampus and ventrolateral prefrontal cortex. Regions responding to negative valence included visual and lateral prefrontal regions, positive valence activated middle temporal and orbitofrontal areas. Importantly, distinct arousal-by-valence interactions were present in anterior insula (negative pictures), and in occipital cortex, parahippocampal gyrus and posterior cingulate (positive pictures). These data demonstrate that the brain not only differentiates between valence and arousal but also responds to specific combinations of these two, thereby highlighting the sophisticated nature of emotion processing in (female) human subjects.
Brain & Cognition, in press
Valence and arousal are thought to be the primary dimensions of human emotion. However, the degree to which valence and arousal interact in determining brain responses to emotional pictures is still elusive. This functional MRI study aimed to delineate neural systems responding to valence and arousal, and their interaction. We measured neural activation in healthy females (N=23) to affective pictures using a 2 (Valence)x2 (Arousal) design. Results show that arousal was preferentially processed by middle temporal gyrus, hippocampus and ventrolateral prefrontal cortex. Regions responding to negative valence included visual and lateral prefrontal regions, positive valence activated middle temporal and orbitofrontal areas. Importantly, distinct arousal-by-valence interactions were present in anterior insula (negative pictures), and in occipital cortex, parahippocampal gyrus and posterior cingulate (positive pictures). These data demonstrate that the brain not only differentiates between valence and arousal but also responds to specific combinations of these two, thereby highlighting the sophisticated nature of emotion processing in (female) human subjects.
ARTICLE UPDATE - An electrophysiological investigation into the automaticity of emotional face processing in high versus low trait anxious individuals
Holmes A, Nielsen MK, Tipper S, Green S.
Cognitive, Affective, Behavioral Neuroscience, 9, 323-334
To examine the extent of automaticity of emotional face processing in high versus low trait anxious participants, event-related potentials (ERPs) were recorded to emotional (fearful, happy) and neutral faces under varying task demands (low load, high load). Results showed that perceptual encoding of emotional faces, as reflected in P1 and early posterior negativity components, was unaffected by the availability of processing resources. In contrast, the postperceptual registration and storage of emotion-related information, as reflected in the late positive potential component at frontal locations, was influenced by the availability of processing resources, and this effect was further modulated by level of trait anxiety. Specifically, frontal ERP augmentations to emotional faces were eliminated in the more demanding task for low trait anxious participants, whereas ERP enhancements to emotional faces were unaffected by task load in high trait anxious participants. This result suggests greater automaticity in processing affective information in high trait anxious participants.
Cognitive, Affective, Behavioral Neuroscience, 9, 323-334
To examine the extent of automaticity of emotional face processing in high versus low trait anxious participants, event-related potentials (ERPs) were recorded to emotional (fearful, happy) and neutral faces under varying task demands (low load, high load). Results showed that perceptual encoding of emotional faces, as reflected in P1 and early posterior negativity components, was unaffected by the availability of processing resources. In contrast, the postperceptual registration and storage of emotion-related information, as reflected in the late positive potential component at frontal locations, was influenced by the availability of processing resources, and this effect was further modulated by level of trait anxiety. Specifically, frontal ERP augmentations to emotional faces were eliminated in the more demanding task for low trait anxious participants, whereas ERP enhancements to emotional faces were unaffected by task load in high trait anxious participants. This result suggests greater automaticity in processing affective information in high trait anxious participants.
ARTICLE UPDATE - Taboo words: The effect of emotion on memory for peripheral information.
Guillet R, Arndt J.
Memory & Cognition, 37, 866-879
In three experiments, we examined memory for peripheral information that occurred in the same context as emotion-inducing information. In the first two experiments, participants studied either a sentence (Experiment 1) or a pair of words (Experiments 2A-2C) containing a neutral peripheral word, as well as a neutral, negative-valence, or taboo word, to induce an emotional response. At retrieval, the participants were asked to recall the neutral peripheral word from a sentence fragment or emotion-inducing word cue. In Experiment 3, we presented word pairs at encoding and tested memory with associative recognition. In all three experiments, memory for peripheral words was enhanced when it was encoded in the presence of emotionally arousing taboo words but not when it was encoded in the presence of words that were only negative in valence. These data are consistent with priority-binding theory (MacKay et al., 2004) and inconsistent with the attention-narrowing hypothesis (Easterbrook, 1959), as well as with object-based binding theory (Mather, 2007).
Memory & Cognition, 37, 866-879
In three experiments, we examined memory for peripheral information that occurred in the same context as emotion-inducing information. In the first two experiments, participants studied either a sentence (Experiment 1) or a pair of words (Experiments 2A-2C) containing a neutral peripheral word, as well as a neutral, negative-valence, or taboo word, to induce an emotional response. At retrieval, the participants were asked to recall the neutral peripheral word from a sentence fragment or emotion-inducing word cue. In Experiment 3, we presented word pairs at encoding and tested memory with associative recognition. In all three experiments, memory for peripheral words was enhanced when it was encoded in the presence of emotionally arousing taboo words but not when it was encoded in the presence of words that were only negative in valence. These data are consistent with priority-binding theory (MacKay et al., 2004) and inconsistent with the attention-narrowing hypothesis (Easterbrook, 1959), as well as with object-based binding theory (Mather, 2007).
Monday, August 10, 2009
ARTICLE UPDATE - Tuning the brain for novelty detection under emotional threat: the role of increasing gamma phase-synchronization.
Garcia-Garcia M, Yordanova J, Kolev V, Domínguez-Borràs J, Escera C.
Neuroimage, in press
Effective orienting of attention towards novel events is crucial for survival, particularly if they occur in a dangerous situation. This is why stimuli with emotional value are more efficient in capturing attention than neutral stimuli, and why the processing of unexpected novel stimuli is enhanced under a negative emotional context. Here we measured the phase-synchronization (PS) of gamma-band responses (GBR) from human EEG scalp-recordings during performance of a visual discrimination task in which task-irrelevant standard and novel sounds were presented in either a neutral or a negative emotional context, in order to elucidate the brain mechanisms by which emotion tunes the processing of novel events. Visual task performance was distracted by novel sounds, and this distraction was enhanced by the negative emotional context. Similarly, gamma PS was enhanced after novel as compared to standard sounds and it was also larger to auditory stimuli in the negative than in the neutral emotional context, reflecting the synchronization of neural networks for increasing of attentional processing. Remarkably, the larger PS increase of GBR after novel sounds in the negative as compared to the neutral emotional context over midline and right frontal regions reveals that a negative emotional context tunes novelty processing by means of the PS of brain activity in the gamma frequency band around 40 Hz in specific neural networks.
Neuroimage, in press
Effective orienting of attention towards novel events is crucial for survival, particularly if they occur in a dangerous situation. This is why stimuli with emotional value are more efficient in capturing attention than neutral stimuli, and why the processing of unexpected novel stimuli is enhanced under a negative emotional context. Here we measured the phase-synchronization (PS) of gamma-band responses (GBR) from human EEG scalp-recordings during performance of a visual discrimination task in which task-irrelevant standard and novel sounds were presented in either a neutral or a negative emotional context, in order to elucidate the brain mechanisms by which emotion tunes the processing of novel events. Visual task performance was distracted by novel sounds, and this distraction was enhanced by the negative emotional context. Similarly, gamma PS was enhanced after novel as compared to standard sounds and it was also larger to auditory stimuli in the negative than in the neutral emotional context, reflecting the synchronization of neural networks for increasing of attentional processing. Remarkably, the larger PS increase of GBR after novel sounds in the negative as compared to the neutral emotional context over midline and right frontal regions reveals that a negative emotional context tunes novelty processing by means of the PS of brain activity in the gamma frequency band around 40 Hz in specific neural networks.
ARTICLE UPDATE - Tell me about it: Neural activity elicited by emotional pictures and preceding descriptions.
Macnamara A, Foti D, Hajcak G.
Emotion, 9, 531-543
Emotional pictures elicit enhanced parietal positivities beginning around 300 ms following stimulus presentation. The magnitude of these responses, however, depends on both intrinsic (stimulus-driven) and extrinsic (context-driven) factors. In the present study, event-related potentials were recorded while participants viewed unpleasant and neutral pictures that were described either more neutrally or more negatively prior to presentation; temporospatial principal components analysis identified early and late positivities: Both emotional images and descriptions had independent and additive effects on early (334 ms) and midlatency (1,066 ms) positivities, whereas the latest positivity (1,688 ms) was sensitive only to description type. Results are discussed with regard to the time course of automatic and controlled processing of emotional stimuli.
Emotion, 9, 531-543
Emotional pictures elicit enhanced parietal positivities beginning around 300 ms following stimulus presentation. The magnitude of these responses, however, depends on both intrinsic (stimulus-driven) and extrinsic (context-driven) factors. In the present study, event-related potentials were recorded while participants viewed unpleasant and neutral pictures that were described either more neutrally or more negatively prior to presentation; temporospatial principal components analysis identified early and late positivities: Both emotional images and descriptions had independent and additive effects on early (334 ms) and midlatency (1,066 ms) positivities, whereas the latest positivity (1,688 ms) was sensitive only to description type. Results are discussed with regard to the time course of automatic and controlled processing of emotional stimuli.
ARTICLE UPDATE - Immediacy bias in emotion perception: Current emotions seem more intense than previous emotions.
Van Boven L, White K, Huber M.
Journal of Experimental Psychology: General, 138, 368-382
People tend to perceive immediate emotions as more intense than previous emotions. This immediacy bias in emotion perception occurred for exposure to emotional but not neutral stimuli (Study 1), when emotional stimuli were separated by both shorter (2 s; Studies 1 and 2) and longer (20 min; Studies 3, 4, and 5) delays, and for emotional reactions to pictures (Studies 1 and 2), films (Studies 3 and 4), and descriptions of terrorist threats (Study 5). The immediacy bias may be partly caused by immediate emotion's salience, and by the greater availability of information about immediate compared with previous emotion. Consistent with emotional salience, when people experienced new emotions, they perceived previous emotions as less intense than they did initially (Studies 3 and 5)-a change in perception that did not occur when people did not experience a new immediate emotion (Study 2). Consistent with emotional availability, reminding people that information about emotions naturally decays from memory reduced the immediacy bias by making previous emotions seem more intense (Study 4). Discussed are implications for psychological theory and other judgments and behaviors.
Journal of Experimental Psychology: General, 138, 368-382
People tend to perceive immediate emotions as more intense than previous emotions. This immediacy bias in emotion perception occurred for exposure to emotional but not neutral stimuli (Study 1), when emotional stimuli were separated by both shorter (2 s; Studies 1 and 2) and longer (20 min; Studies 3, 4, and 5) delays, and for emotional reactions to pictures (Studies 1 and 2), films (Studies 3 and 4), and descriptions of terrorist threats (Study 5). The immediacy bias may be partly caused by immediate emotion's salience, and by the greater availability of information about immediate compared with previous emotion. Consistent with emotional salience, when people experienced new emotions, they perceived previous emotions as less intense than they did initially (Studies 3 and 5)-a change in perception that did not occur when people did not experience a new immediate emotion (Study 2). Consistent with emotional availability, reminding people that information about emotions naturally decays from memory reduced the immediacy bias by making previous emotions seem more intense (Study 4). Discussed are implications for psychological theory and other judgments and behaviors.
ARTICLE UPDATE - What factors need to be considered to understand emotional memories?
Kensinger EA.
Emotional Review, 1, 120-121
In my original review (this issue), I proposed that to understand the effects of emotion on memory accuracy, we must look beyond effects of arousal and consider the contribution of valence. In discussing this proposal, the commentators raise a number of excellent points that hone in on the question of when valence does (and does not) account for emotion's effects on memory accuracy. Though future research will be required to resolve this issue more fully, in this brief response, I address some of the concerns outlined by the commentators and suggest a few steps that may help to elucidate the dimensions that should be incorporated in models of emotional memory.
Emotional Review, 1, 120-121
In my original review (this issue), I proposed that to understand the effects of emotion on memory accuracy, we must look beyond effects of arousal and consider the contribution of valence. In discussing this proposal, the commentators raise a number of excellent points that hone in on the question of when valence does (and does not) account for emotion's effects on memory accuracy. Though future research will be required to resolve this issue more fully, in this brief response, I address some of the concerns outlined by the commentators and suggest a few steps that may help to elucidate the dimensions that should be incorporated in models of emotional memory.
ARTICLE UPDATE - Why people rehearse their memories: Frequency of use and relations to the intensity of emotions associated with autobiographical memo
Walker WR, Skowronski JJ, Gibbons JA, Vogl RJ, Ritchie TD.
Memory, in press
People may choose to rehearse their autobiographical memories in silence or to disclose their memories with other people. This paper focuses on five types of memory rehearsal: involuntary rehearsal, rehearsal to maintain an event memory, rehearsal to re-experience the emotion of an event, rehearsal to understand an event, or rehearsal for social communication. A total of 337 participants recalled event memories, provided estimates of how often each event was rehearsed and for what reason, and rated the affective characteristics of the events. Rehearsal frequency was highest for social communication and lowest for rehearsals aimed at understanding events. For many rehearsal types, rehearsal was more frequent for positive than negative events. Frequently rehearsed events tended to show less affective fading. The pattern changed when events were socially rehearsed. For positive events, increased social rehearsal was related to a reduction in affective fading. For negative events, increased social rehearsal was associated with increased affective fading.
Memory, in press
People may choose to rehearse their autobiographical memories in silence or to disclose their memories with other people. This paper focuses on five types of memory rehearsal: involuntary rehearsal, rehearsal to maintain an event memory, rehearsal to re-experience the emotion of an event, rehearsal to understand an event, or rehearsal for social communication. A total of 337 participants recalled event memories, provided estimates of how often each event was rehearsed and for what reason, and rated the affective characteristics of the events. Rehearsal frequency was highest for social communication and lowest for rehearsals aimed at understanding events. For many rehearsal types, rehearsal was more frequent for positive than negative events. Frequently rehearsed events tended to show less affective fading. The pattern changed when events were socially rehearsed. For positive events, increased social rehearsal was related to a reduction in affective fading. For negative events, increased social rehearsal was associated with increased affective fading.
Monday, August 03, 2009
ARTICLE UPDATE - Normative data on development of neural and behavioral mechanisms underlying attention orienting toward social-emotional stimuli: An
Lindstrom K, Guyer AE, Mogg K, Bradley BP, Fox NA, Ernst M, Nelson EE, Leibenluft E, Britton JC, Monk CS, Pine DS, Bar-Haim Y.
Brain Research, in press
The ability of positive and negative facial signals to influence attention orienting is crucial to social functioning. Given the dramatic developmental change in neural architecture supporting social function, positive and negative facial cues may influence attention orienting differently in relatively young or old individuals. However, virtually no research examines such age-related differences in the neural circuitry supporting attention orienting to emotional faces. We examined age-related correlations in attention-orienting biases to positive and negative face emotions in a healthy sample (N=37; 9-40 years old) using functional magnetic resonance imaging and a dot-probe task. The dot-probe task in an fMRI setting yields both behavioral and neural indices of attention biases towards or away from an emotional cue (happy or angry face). In the full sample, angry-face attention bias scores did not correlate with age, and age did not correlate with brain activation to angry faces. However, age did positively correlate with attention bias towards happy faces; age also negatively correlated with left cuneus and left caudate activation to a happy-bias fMRI contrast. Secondary analyses suggested age-related changes in attention bias to happy faces. The tendency in younger children to direct attention away from happy faces (relative to neutral faces) was diminished in the older age groups, in tandem with increasing neural deactivation. Implications for future work on developmental changes in attention-emotion processing are discussed.
Brain Research, in press
The ability of positive and negative facial signals to influence attention orienting is crucial to social functioning. Given the dramatic developmental change in neural architecture supporting social function, positive and negative facial cues may influence attention orienting differently in relatively young or old individuals. However, virtually no research examines such age-related differences in the neural circuitry supporting attention orienting to emotional faces. We examined age-related correlations in attention-orienting biases to positive and negative face emotions in a healthy sample (N=37; 9-40 years old) using functional magnetic resonance imaging and a dot-probe task. The dot-probe task in an fMRI setting yields both behavioral and neural indices of attention biases towards or away from an emotional cue (happy or angry face). In the full sample, angry-face attention bias scores did not correlate with age, and age did not correlate with brain activation to angry faces. However, age did positively correlate with attention bias towards happy faces; age also negatively correlated with left cuneus and left caudate activation to a happy-bias fMRI contrast. Secondary analyses suggested age-related changes in attention bias to happy faces. The tendency in younger children to direct attention away from happy faces (relative to neutral faces) was diminished in the older age groups, in tandem with increasing neural deactivation. Implications for future work on developmental changes in attention-emotion processing are discussed.
Monday, July 27, 2009
ARTICLE UPDATE - Modulation of Perception and Brain Activity by Predictable Trajectories of Facial Expressions.
Furl N, van Rijsbergen NJ, Kiebel SJ, Friston KJ, Treves A, Dolan RJ.
Cerebral Cortex, in press
People track facial expression dynamics with ease to accurately perceive distinct emotions. Although the superior temporal sulcus (STS) appears to possess mechanisms for perceiving changeable facial attributes such as expressions, the nature of the underlying neural computations is not known. Motivated by novel theoretical accounts, we hypothesized that visual and motor areas represent expressions as anticipated motion trajectories. Using magnetoencephalography, we show predictable transitions between fearful and neutral expressions (compared with scrambled and static presentations) heighten activity in visual cortex as quickly as 165 ms poststimulus onset and later (237 ms) engage fusiform gyrus, STS and premotor areas. Consistent with proposed models of biological motion representation, we suggest that visual areas predictively represent coherent facial trajectories. We show that such representations bias emotion perception of subsequent static faces, suggesting that facial movements elicit predictions that bias perception. Our findings reveal critical processes evoked in the perception of dynamic stimuli such as facial expressions, which can endow perception with temporal continuity.
Cerebral Cortex, in press
People track facial expression dynamics with ease to accurately perceive distinct emotions. Although the superior temporal sulcus (STS) appears to possess mechanisms for perceiving changeable facial attributes such as expressions, the nature of the underlying neural computations is not known. Motivated by novel theoretical accounts, we hypothesized that visual and motor areas represent expressions as anticipated motion trajectories. Using magnetoencephalography, we show predictable transitions between fearful and neutral expressions (compared with scrambled and static presentations) heighten activity in visual cortex as quickly as 165 ms poststimulus onset and later (237 ms) engage fusiform gyrus, STS and premotor areas. Consistent with proposed models of biological motion representation, we suggest that visual areas predictively represent coherent facial trajectories. We show that such representations bias emotion perception of subsequent static faces, suggesting that facial movements elicit predictions that bias perception. Our findings reveal critical processes evoked in the perception of dynamic stimuli such as facial expressions, which can endow perception with temporal continuity.
ARTICLE UPDATE - Event-related potentials to task-irrelevant changes in facial expressions.
Astikainen P, Hietanen JK.
Behavioural Brain Function, in press
ABSTRACT: BACKGROUND: Numerous previous experiments have used oddball paradigm to study change detection. This paradigm is applied here to study change detection of facial expressions in a context which demands abstraction of the emotional expression-related facial features among other changing facial features. METHODS: Event-related potentials (ERPs) were recorded in adult humans engaged in a demanding auditory task. In an oddball paradigm, repeated pictures of faces with a neutral expression ('standard', p = .9) were rarely replaced by pictures with a fearful ('fearful deviant', p = .05) or happy ('happy deviant', p = .05) expression. Importantly, facial identities changed from picture to picture. Thus, change detection required abstraction of facial expression from changes in several low-level visual features. RESULTS: ERPs to both types of deviants differed from those to standards. At occipital electrode sites, ERPs to deviants were more negative than ERPs to standards at 150-180 ms and 280-320 ms post-stimulus. A positive shift to deviants at fronto-central electrode sites in the analysis window of 130-170 ms post-stimulus was also found. Waveform analysis computed as point-wise comparisons between the amplitudes elicited by standards and deviants revealed that the occipital negativity emerged earlier to happy deviants than to fearful deviants (after 140 ms versus 160 ms post-stimulus, respectively). In turn, the anterior positivity was earlier to fearful deviants than to happy deviants (110 ms versus 120 ms post-stimulus, respectively). CONCLUSION: ERP amplitude differences between emotional and neutral expressions indicated pre-attentive change detection of facial expressions among neutral faces. The posterior negative difference at 150-180 ms latency resembled visual mismatch negativity (vMMN) - an index of pre-attentive change detection previously studied only to changes in low-level features in vision. The positive anterior difference in ERPs at 130-170 ms post-stimulus probably indexed pre-attentive attention orienting towards emotionally significant changes. The results show that the human brain can abstract emotion related features of faces while engaged to a demanding task in another sensory modality.
Behavioural Brain Function, in press
ABSTRACT: BACKGROUND: Numerous previous experiments have used oddball paradigm to study change detection. This paradigm is applied here to study change detection of facial expressions in a context which demands abstraction of the emotional expression-related facial features among other changing facial features. METHODS: Event-related potentials (ERPs) were recorded in adult humans engaged in a demanding auditory task. In an oddball paradigm, repeated pictures of faces with a neutral expression ('standard', p = .9) were rarely replaced by pictures with a fearful ('fearful deviant', p = .05) or happy ('happy deviant', p = .05) expression. Importantly, facial identities changed from picture to picture. Thus, change detection required abstraction of facial expression from changes in several low-level visual features. RESULTS: ERPs to both types of deviants differed from those to standards. At occipital electrode sites, ERPs to deviants were more negative than ERPs to standards at 150-180 ms and 280-320 ms post-stimulus. A positive shift to deviants at fronto-central electrode sites in the analysis window of 130-170 ms post-stimulus was also found. Waveform analysis computed as point-wise comparisons between the amplitudes elicited by standards and deviants revealed that the occipital negativity emerged earlier to happy deviants than to fearful deviants (after 140 ms versus 160 ms post-stimulus, respectively). In turn, the anterior positivity was earlier to fearful deviants than to happy deviants (110 ms versus 120 ms post-stimulus, respectively). CONCLUSION: ERP amplitude differences between emotional and neutral expressions indicated pre-attentive change detection of facial expressions among neutral faces. The posterior negative difference at 150-180 ms latency resembled visual mismatch negativity (vMMN) - an index of pre-attentive change detection previously studied only to changes in low-level features in vision. The positive anterior difference in ERPs at 130-170 ms post-stimulus probably indexed pre-attentive attention orienting towards emotionally significant changes. The results show that the human brain can abstract emotion related features of faces while engaged to a demanding task in another sensory modality.
ARTICLE UPDATE - Evidence for mirror systems in emotions.
Bastiaansen JA, Thioux M, Keysers C.
Phil. Trans. R. Soc. B, 364, 2391 - 2404
Why do we feel tears well up when we see a loved one cry? Why do we wince when we see other people hurt themselves? This review addresses these questions from the perspective of embodied simulation: observing the actions and tactile sensations of others activates premotor, posterior parietal and somatosensory regions in the brain of the observer which are also active when performing similar movements and feeling similar sensations. We will show that seeing the emotions of others also recruits regions involved in experiencing similar emotions, although there does not seem to be a reliable mapping of particular emotions onto particular brain regions. Instead, emotion simulation seems to involve a mosaic of affective, motor and somatosensory components. The relative contributions of these components to a particular emotion and their interrelationship are largely unknown, although recent experimental evidence suggests that motor simulation may be a trigger for the simulation of associated feeling states. This mosaic of simulations may be necessary for generating the compelling insights we have into the feelings of others. Through their integration with, and modulation by, higher cognitive functions, they could be at the core of important social functions, including empathy, mind reading and social learning.
Phil. Trans. R. Soc. B, 364, 2391 - 2404
Why do we feel tears well up when we see a loved one cry? Why do we wince when we see other people hurt themselves? This review addresses these questions from the perspective of embodied simulation: observing the actions and tactile sensations of others activates premotor, posterior parietal and somatosensory regions in the brain of the observer which are also active when performing similar movements and feeling similar sensations. We will show that seeing the emotions of others also recruits regions involved in experiencing similar emotions, although there does not seem to be a reliable mapping of particular emotions onto particular brain regions. Instead, emotion simulation seems to involve a mosaic of affective, motor and somatosensory components. The relative contributions of these components to a particular emotion and their interrelationship are largely unknown, although recent experimental evidence suggests that motor simulation may be a trigger for the simulation of associated feeling states. This mosaic of simulations may be necessary for generating the compelling insights we have into the feelings of others. Through their integration with, and modulation by, higher cognitive functions, they could be at the core of important social functions, including empathy, mind reading and social learning.
ARTICLE UPDATE - N400 during recognition of voice identity and vocal affect.
Toivonen M, Rämä P.
Neuroreport, in press
This study explored whether neural processes underlying recognition of speaker's voice and vocal affect are dissociable by measuring event-related potentials. Individuals were asked to identify a target emotion, or a target (congruent) speaker among distracter (incongruent) emotions or speakers. The incongruent condition elicited more negative N400-like response during both tasks, but the distributions differed. Although the response in speaker task was more pronounced at frontal than posterior recording sites, in emotion task, the opposite was true. Furthermore, the response was more pronounced at the left recording sites for speaker task and more pronounced at the right recording sites for emotion task. The present results suggest that neural substrates involved in processing speaker identity are different from those responsible for processing vocal affect.
Neuroreport, in press
This study explored whether neural processes underlying recognition of speaker's voice and vocal affect are dissociable by measuring event-related potentials. Individuals were asked to identify a target emotion, or a target (congruent) speaker among distracter (incongruent) emotions or speakers. The incongruent condition elicited more negative N400-like response during both tasks, but the distributions differed. Although the response in speaker task was more pronounced at frontal than posterior recording sites, in emotion task, the opposite was true. Furthermore, the response was more pronounced at the left recording sites for speaker task and more pronounced at the right recording sites for emotion task. The present results suggest that neural substrates involved in processing speaker identity are different from those responsible for processing vocal affect.
Monday, July 20, 2009
ARTICLE UPDATE - Emotion words, regardless of polarity, have a processing advantage over neutral words.
Kousta ST, Vinson DP, Vigliocco G.
Cognition, in press
Despite increasing interest in the interface between emotion and cognition, the role of emotion in cognitive tasks is unclear. According to one hypothesis, negative valence is more relevant for survival and is associated with a general slowdown of the processing of stimuli, due to a defense mechanism that freezes activity in the face of threat. According to a different hypothesis which does not posit a privileged role for the aversive system, valence, regardless of polarity, facilitates processing due to the relevance of both negative and positive stimuli for survival and for the attainment of goals. Here, we present evidence that emotional valence has an overall facilitatory role in the processing of verbal stimuli, providing support for the latter hypothesis. We found no asymmetry between negative and positive words and suggest that previous findings of such an asymmetry can be attributed to failure to control for a number of critical lexical variables and to a sampling bias.
Cognition, in press
Despite increasing interest in the interface between emotion and cognition, the role of emotion in cognitive tasks is unclear. According to one hypothesis, negative valence is more relevant for survival and is associated with a general slowdown of the processing of stimuli, due to a defense mechanism that freezes activity in the face of threat. According to a different hypothesis which does not posit a privileged role for the aversive system, valence, regardless of polarity, facilitates processing due to the relevance of both negative and positive stimuli for survival and for the attainment of goals. Here, we present evidence that emotional valence has an overall facilitatory role in the processing of verbal stimuli, providing support for the latter hypothesis. We found no asymmetry between negative and positive words and suggest that previous findings of such an asymmetry can be attributed to failure to control for a number of critical lexical variables and to a sampling bias.
ARTICLE UPDATE - Amygdala activation predicts gaze toward fearful eyes.
Gamer M, Büchel C.
The Journal of Neuroscience, 29, 9123-9126
The human amygdala can be robustly activated by presenting fearful faces, and it has been speculated that this activation has functional relevance for redirecting the gaze toward the eye region. To clarify this relationship between amygdala activation and gaze-orienting behavior, functional magnetic resonance imaging data and eye movements were simultaneously acquired in the current study during the evaluation of facial expressions. Fearful, angry, happy, and neutral faces were briefly presented to healthy volunteers in an event-related manner. We controlled for the initial fixation by unpredictably shifting the faces downward or upward on each trial, such that the eyes or the mouth were presented at fixation. Across emotional expressions, participants showed a bias to shift their gaze toward the eyes, but the magnitude of this effect followed the distribution of diagnostically relevant regions in the face. Amygdala activity was specifically enhanced for fearful faces with the mouth aligned to fixation, and this differential activation predicted gazing behavior preferentially targeting the eye region. These results reveal a direct role of the amygdala in reflexive gaze initiation toward fearfully widened eyes. They mirror deficits observed in patients with amygdala lesions and open a window for future studies on patients with autism spectrum disorder, in which deficits in emotion recognition, probably related to atypical gaze patterns and abnormal amygdala activation, have been observed.
The Journal of Neuroscience, 29, 9123-9126
The human amygdala can be robustly activated by presenting fearful faces, and it has been speculated that this activation has functional relevance for redirecting the gaze toward the eye region. To clarify this relationship between amygdala activation and gaze-orienting behavior, functional magnetic resonance imaging data and eye movements were simultaneously acquired in the current study during the evaluation of facial expressions. Fearful, angry, happy, and neutral faces were briefly presented to healthy volunteers in an event-related manner. We controlled for the initial fixation by unpredictably shifting the faces downward or upward on each trial, such that the eyes or the mouth were presented at fixation. Across emotional expressions, participants showed a bias to shift their gaze toward the eyes, but the magnitude of this effect followed the distribution of diagnostically relevant regions in the face. Amygdala activity was specifically enhanced for fearful faces with the mouth aligned to fixation, and this differential activation predicted gazing behavior preferentially targeting the eye region. These results reveal a direct role of the amygdala in reflexive gaze initiation toward fearfully widened eyes. They mirror deficits observed in patients with amygdala lesions and open a window for future studies on patients with autism spectrum disorder, in which deficits in emotion recognition, probably related to atypical gaze patterns and abnormal amygdala activation, have been observed.
Monday, July 13, 2009
ARTICLE UPDATE - Short-term antidepressant treatment modulates amygdala response to happy faces.
Norbury R, Taylor MJ, Selvaraj S, Murphy SE, Harmer CJ, Cowen PJ.
Psychopharmacology, in press
RATIONALE: We have previously demonstrated that antidepressant medication facilitates the processing of positive affective stimuli in healthy volunteers. These early effects of antidepressants may be an important component in the therapeutic effects of antidepressant treatment in patients with depression and anxiety. OBJECTIVES: Here we used functional magnetic resonance imaging in a double-blind, randomised, placebo-controlled between-groups design to investigate the effects of short-term (7-10 days) treatment with the selective serotonin reuptake inhibitor, citalopram, on the amygdala response to positive and negative facial expressions in healthy volunteers. RESULTS: Citalopram was associated with increased amygdala activation to happy faces relative to placebo control, without changes in levels of mood or anxiety. CONCLUSIONS: These early, direct effects of antidepressant administration on emotional processing are consistent with a cognitive neuropsychological model of antidepressant action.
Psychopharmacology, in press
RATIONALE: We have previously demonstrated that antidepressant medication facilitates the processing of positive affective stimuli in healthy volunteers. These early effects of antidepressants may be an important component in the therapeutic effects of antidepressant treatment in patients with depression and anxiety. OBJECTIVES: Here we used functional magnetic resonance imaging in a double-blind, randomised, placebo-controlled between-groups design to investigate the effects of short-term (7-10 days) treatment with the selective serotonin reuptake inhibitor, citalopram, on the amygdala response to positive and negative facial expressions in healthy volunteers. RESULTS: Citalopram was associated with increased amygdala activation to happy faces relative to placebo control, without changes in levels of mood or anxiety. CONCLUSIONS: These early, direct effects of antidepressant administration on emotional processing are consistent with a cognitive neuropsychological model of antidepressant action.
Monday, July 06, 2009
ARTICLE UPDATE - Human brain responsivity to masked different intensities of fearful eye whites: An ERP study.
Feng W, Luo W, Liao Y, Wang N, Gan T, Luo Y.
Brain Research, in press
Previous studies have shown differential event-related potentials (ERPs) to intensities of fearful facial expressions. There are indications that the eyes may be particularly relevant for the recognition of fearful expressions, even the amount of white sclera exposed above and on sides of the dark pupil could activate the amygdala response. To investigate whether the ERP differences between intensities of fearful expressions are driven by the differential salience of the eyes in the fearful faces, ERPs were measured within a backward masking paradigm, where observers were asked to do a gender decision task with male and female neutral faces. The emotional stimuli used were low-intensity (50%), prototypical (100%), and caricatured (150%) fearful eye whites that were derived from corresponding intensities of fearful faces respectively. Three groups of white squares that have the same pixels as the eye whites were created as control conditions. Analysis of the ERP data showed a linear increase in amplitudes of the parietal-occipital P120 by three intensities of fearful eye whites. These ERP effects were proved sensitive to intensities of negative emotions but not to the simple physical features as the same patterns of differences were not observed on white squares. Larger parietal-occipital P250 amplitudes were observed for caricatured 150% than low-intensity 50% fearful eye-white. It might reflect the subcortical pathway of emotion-specific, fearful processing. The results demonstrate that the human brain is sensitive to intensities of fear, even if just shown intensities of fearful eye-white in the absence of awareness.
Brain Research, in press
Previous studies have shown differential event-related potentials (ERPs) to intensities of fearful facial expressions. There are indications that the eyes may be particularly relevant for the recognition of fearful expressions, even the amount of white sclera exposed above and on sides of the dark pupil could activate the amygdala response. To investigate whether the ERP differences between intensities of fearful expressions are driven by the differential salience of the eyes in the fearful faces, ERPs were measured within a backward masking paradigm, where observers were asked to do a gender decision task with male and female neutral faces. The emotional stimuli used were low-intensity (50%), prototypical (100%), and caricatured (150%) fearful eye whites that were derived from corresponding intensities of fearful faces respectively. Three groups of white squares that have the same pixels as the eye whites were created as control conditions. Analysis of the ERP data showed a linear increase in amplitudes of the parietal-occipital P120 by three intensities of fearful eye whites. These ERP effects were proved sensitive to intensities of negative emotions but not to the simple physical features as the same patterns of differences were not observed on white squares. Larger parietal-occipital P250 amplitudes were observed for caricatured 150% than low-intensity 50% fearful eye-white. It might reflect the subcortical pathway of emotion-specific, fearful processing. The results demonstrate that the human brain is sensitive to intensities of fear, even if just shown intensities of fearful eye-white in the absence of awareness.
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