Amit Anand, Yu Li, Yang Wang, Jingwei Wu, Sujuan Gao, Lubna Bukharia, Vincent P. Mathews, Andrew Kalnin and Mark J. Lowe
Biological Psychiatry, 57, 1079-1088
Background
Functional imaging studies indicate that imbalances in cortico-limbic activity and connectivity may underlie the pathophysiology of MDD. In this study, using functional Magnetic Resonance Imaging (fMRI), we investigated differences in cortico-limbic activity and connectivity between depressed patients and healthy controls.
Methods
Fifteen unmedicated unipolar depressed patients and 15 matched healthy subjects underwent fMRI during which they first completed a conventional block-design activation experiment in which they were exposed to negative and neutral pictures. Next, low frequency blood oxygenation dependent (BOLD) related fluctuations (LFBF) data were acquired at rest and during steady-state exposure to neutral, positive and negative pictures. LFBF correlations were calculated between anterior cingulate cortex (ACC) and limbic regions – amygdala (AMYG), pallidostriatum (PST) and medial thalamus (MTHAL) and used as a measure of cortico-limbic connectivity.
Results
Depressed patients had increased activation of cortical and limbic regions. At rest and during exposure to neutral, positive, and negative pictures cortico-limbic LFBF correlations were decreased in depressed patients compared to healthy subjects.
Conclusions
The finding of increased activation of limbic regions and decreased LFBF correlations between ACC and limbic regions is consistent with the hypothesis that decreased cortical regulation of limbic activation in response to negative stimuli may be present in depression.
Thursday, May 05, 2005
Friday, April 29, 2005
ARTICLE UPDATE - Emotion-based learning and central executive resources: an investigation of intuition and the Iowa Gambling Task.
Turnbull OH, Evans CE, Bunce A, Carzolio B, O'connor J.
Brain and Cognition, 57, 244-7.
The role of emotion in complex decision-making can be assessed on the Iowa Gambling Task (IGT), a widely used neuropsychological measure that may tap a different aspect of executive function than that assessed by conventional measures. Most notably, the 'feeling' about which decks are good or bad, often described in relation to IGT performance, seems reminiscent of decision-making based on intuition-linked to a long history of research in decision-making contrasting the 'intuition' versus 'reasoning' styles of problem solving. To test the claim that the performance on the IGT relies more on emotion-based learning than conventional executive resources for normal performance, a group of participants completed the IGT simultaneously with one of two secondary-tasks, one of which (random number generation) is known to load executive resources. A third group performed the IGT with no secondary-task. If performance on the IGT requires the properties associated with intuitive operations, then participants should either show no disruption when completing a secondary-task, or at least show no selective disruption on a secondary-task that loads for executive function. The rate of learning in the three groups was not significantly different. This suggests that the sorts of cognitive resources loaded by traditional executive tasks such as random number generation do not overlap, in the cognitive architecture, with the emotion-based learning skills that are required for Iowa Gambling Task performance. The findings of the present study are also consistent with a previous claim of the Iowa group that emotion-based learning and working memory resources are doubly dissociable.
Brain and Cognition, 57, 244-7.
The role of emotion in complex decision-making can be assessed on the Iowa Gambling Task (IGT), a widely used neuropsychological measure that may tap a different aspect of executive function than that assessed by conventional measures. Most notably, the 'feeling' about which decks are good or bad, often described in relation to IGT performance, seems reminiscent of decision-making based on intuition-linked to a long history of research in decision-making contrasting the 'intuition' versus 'reasoning' styles of problem solving. To test the claim that the performance on the IGT relies more on emotion-based learning than conventional executive resources for normal performance, a group of participants completed the IGT simultaneously with one of two secondary-tasks, one of which (random number generation) is known to load executive resources. A third group performed the IGT with no secondary-task. If performance on the IGT requires the properties associated with intuitive operations, then participants should either show no disruption when completing a secondary-task, or at least show no selective disruption on a secondary-task that loads for executive function. The rate of learning in the three groups was not significantly different. This suggests that the sorts of cognitive resources loaded by traditional executive tasks such as random number generation do not overlap, in the cognitive architecture, with the emotion-based learning skills that are required for Iowa Gambling Task performance. The findings of the present study are also consistent with a previous claim of the Iowa group that emotion-based learning and working memory resources are doubly dissociable.
ARTICLE UPDATE - The dark side of emotion in decision-making: when individuals with decreased emotional reactions make more advantageous decisions.
Shiv B, Loewenstein G, Bechara A.
Cognitive Brain Research,23, 85-92
Can dysfunction in neural systems subserving emotion lead, under certain circumstances, to more advantageous decisions? To answer this question, we investigated how individuals with substance dependence (ISD), patients with stable focal lesions in brain regions related to emotion (lesion patients), and normal participants (normal controls) made 20 rounds of investment decisions. Like lesion patients, ISD made more advantageous decisions and ultimately earned more money from their investments than the normal controls. When normal controls either won or lost money on an investment round, they adopted a conservative strategy and became more reluctant to invest on the subsequent round, suggesting that they were more affected than lesion patients and ISD by the outcomes of decisions made in the previous rounds.
Cognitive Brain Research,23, 85-92
Can dysfunction in neural systems subserving emotion lead, under certain circumstances, to more advantageous decisions? To answer this question, we investigated how individuals with substance dependence (ISD), patients with stable focal lesions in brain regions related to emotion (lesion patients), and normal participants (normal controls) made 20 rounds of investment decisions. Like lesion patients, ISD made more advantageous decisions and ultimately earned more money from their investments than the normal controls. When normal controls either won or lost money on an investment round, they adopted a conservative strategy and became more reluctant to invest on the subsequent round, suggesting that they were more affected than lesion patients and ISD by the outcomes of decisions made in the previous rounds.
ARTICLE UPDATE - Event-related potentials related to normal and morphed emotional faces.
Balconi M, Lucchiari C.
Journal of Psychology, 139, 176-92.
S. Bentin and L. Y. Deouell (2000) have suggested that face recognition is achieved through a special-purpose neural mechanism, and its existence can be identified by a specific event-related potential (ERP) correlate, the N170 effect. In the present study, the authors explored the structural significance of N170 by comparing normal vs. morphed stimuli. They used a morphing procedure that allows a fine modification of some perceptual details (first-order relations). The authors also aimed to verify the independence of face identification from other cognitive mechanisms, such as comprehension of emotional facial expressions, by applying an emotion-by-emotion analysis to examine the emotional effect on N170 ERP variation. They analyzed the peak amplitude and latency variables in the temporal window of 120-180 ms. The ERP correlate showed a classic N170 ERP effect, more negative and more posteriorly distributed for morphed faces compared with normal faces. In addition, they found a lateralization effect, with a greater right-side distribution of the N170, but not directly correlated to the morphed or normal conditions. Two cognitive codes, structural and expression, are discussed, and the results are compared with the multilevel model proposed by V. Bruce and A. W. Young (1986, 1998).
Journal of Psychology, 139, 176-92.
S. Bentin and L. Y. Deouell (2000) have suggested that face recognition is achieved through a special-purpose neural mechanism, and its existence can be identified by a specific event-related potential (ERP) correlate, the N170 effect. In the present study, the authors explored the structural significance of N170 by comparing normal vs. morphed stimuli. They used a morphing procedure that allows a fine modification of some perceptual details (first-order relations). The authors also aimed to verify the independence of face identification from other cognitive mechanisms, such as comprehension of emotional facial expressions, by applying an emotion-by-emotion analysis to examine the emotional effect on N170 ERP variation. They analyzed the peak amplitude and latency variables in the temporal window of 120-180 ms. The ERP correlate showed a classic N170 ERP effect, more negative and more posteriorly distributed for morphed faces compared with normal faces. In addition, they found a lateralization effect, with a greater right-side distribution of the N170, but not directly correlated to the morphed or normal conditions. Two cognitive codes, structural and expression, are discussed, and the results are compared with the multilevel model proposed by V. Bruce and A. W. Young (1986, 1998).
ARTICLE UPDATE - Selective effects of emotion on the phenomenal characteristics of autobiographical memories.
Schaefer A, Philippot P.
Memory, 13, 148-60.
The present study investigates the emotional determinants of the phenomenal characteristics of autobiographical memories. A total of 84 participants completed the Memory Characteristics Questionnaire (MCQ, Johnson, Foley, Suengas, & Raye, 1988) after retrieving and orally describing a negative, a positive, and a neutral autobiographical memory. In addition, self-report and physiological measures of emotional state at retrieval were recorded. Results suggest that recall of perceptual, sensory, and semantic elements is better for emotional memories than for neutral ones. This difference is not significant for contextual and temporal aspects, suggesting that emotional memories are more vivid but no more specific than are neutral ones. In addition, positive memories yielded higher MCQ ratings than did negative memories for sensory, temporal, and contextual aspects. Finally, correlations suggest a positive relation between emotional state at retrieval and level of phenomenal detail of retrieved memories. Results are interpreted in terms of multilevel models of emotion and of Conway and Pleydell-Pearce's (2000) model.
Memory, 13, 148-60.
The present study investigates the emotional determinants of the phenomenal characteristics of autobiographical memories. A total of 84 participants completed the Memory Characteristics Questionnaire (MCQ, Johnson, Foley, Suengas, & Raye, 1988) after retrieving and orally describing a negative, a positive, and a neutral autobiographical memory. In addition, self-report and physiological measures of emotional state at retrieval were recorded. Results suggest that recall of perceptual, sensory, and semantic elements is better for emotional memories than for neutral ones. This difference is not significant for contextual and temporal aspects, suggesting that emotional memories are more vivid but no more specific than are neutral ones. In addition, positive memories yielded higher MCQ ratings than did negative memories for sensory, temporal, and contextual aspects. Finally, correlations suggest a positive relation between emotional state at retrieval and level of phenomenal detail of retrieved memories. Results are interpreted in terms of multilevel models of emotion and of Conway and Pleydell-Pearce's (2000) model.
ARTICLE UPDATE - Emotion words are remembered better in the left ear.
Sim TC, Martinez C.
Laterality;10, 149-59.
In dichotic listening studies, numerous investigators have shown a left ear advantage (i.e., right hemisphere superiority), when judging emotional tone of speech. In the present study, dichotic word-pairs of emotion and non-emotion words were presented to participants who were instructed to recall the entire list in each block. Unlike other studies in which participants responded to emotional intonations, participants in the present investigation listened to stimuli that were spoken in a neutral intonation. A total of 62 participants listened to emotion (e.g., loving) and non-emotion (e.g., combine) words that were dichotically presented. The results showed a left ear advantage for emotion words. This finding provides strong support for the right-hemisphere hypothesis in the form of a stronger memory for emotion words presented to the left ear. The findings are consistent with the role of the right hemisphere in the perception of emotional information.
Laterality;10, 149-59.
In dichotic listening studies, numerous investigators have shown a left ear advantage (i.e., right hemisphere superiority), when judging emotional tone of speech. In the present study, dichotic word-pairs of emotion and non-emotion words were presented to participants who were instructed to recall the entire list in each block. Unlike other studies in which participants responded to emotional intonations, participants in the present investigation listened to stimuli that were spoken in a neutral intonation. A total of 62 participants listened to emotion (e.g., loving) and non-emotion (e.g., combine) words that were dichotically presented. The results showed a left ear advantage for emotion words. This finding provides strong support for the right-hemisphere hypothesis in the form of a stronger memory for emotion words presented to the left ear. The findings are consistent with the role of the right hemisphere in the perception of emotional information.
ARTICLE UPDATE - Emotional memory: Separating content and context.
Medford N, Phillips ML, Brierley B, Brammer M, Bullmore ET, David AS
Psychiatry Research, 138, 247-258.
It is now well established that emotion enhances episodic memory. However, it remains unclear whether the same neural processes underlie enhancement of memory for both emotional stimuli and neutral stimuli encoded in an emotive context. We designed an experiment that specifically attempted to separate these effects and that was validated on 30 participants. We then used functional magnetic resonance imaging (fMRI) to examine the neural correlates of encoding and retrieval of the two classes of stimuli in 12 healthy male volunteers. We predicted that aversive emotional context would enhance memory regardless of content and that activation of anterior cingulate would be inversely related to retrieval of aversive items. Both predictions were supported. Furthermore we demonstrated apparent asymmetrical lateralisation of activation in the hippocampal/parahippocampal complex during recognition of words from aversive sentences: more left-sided activation for neutral words from aversive contexts, and more right-sided activation for aversive content words. These findings, if applicable to the wider population, may have application in a range of psychiatric disorders where interactions between emotion and cognition are relevant.
Psychiatry Research, 138, 247-258.
It is now well established that emotion enhances episodic memory. However, it remains unclear whether the same neural processes underlie enhancement of memory for both emotional stimuli and neutral stimuli encoded in an emotive context. We designed an experiment that specifically attempted to separate these effects and that was validated on 30 participants. We then used functional magnetic resonance imaging (fMRI) to examine the neural correlates of encoding and retrieval of the two classes of stimuli in 12 healthy male volunteers. We predicted that aversive emotional context would enhance memory regardless of content and that activation of anterior cingulate would be inversely related to retrieval of aversive items. Both predictions were supported. Furthermore we demonstrated apparent asymmetrical lateralisation of activation in the hippocampal/parahippocampal complex during recognition of words from aversive sentences: more left-sided activation for neutral words from aversive contexts, and more right-sided activation for aversive content words. These findings, if applicable to the wider population, may have application in a range of psychiatric disorders where interactions between emotion and cognition are relevant.
Wednesday, April 27, 2005
ARTICLE UPDATE - The role of the human amygdala in the production of conditioned fear responses
David C. Knight, Hanh T. Nguyen and Peter A. Bandettini
NeuroImage, in press
The amygdala plays a central role in the acquisition and expression of fear memories. Laboratory animal studies indicate that the amygdala both receives sensory information and produces learned behavioral and autonomic fear responses. However, prior functional imaging research in humans has largely focused on amygdala activity elicited by fearful stimuli, giving less attention to this region's role in the production of fear responses. In contrast, the present study used functional magnetic resonance imaging to investigate the amygdala's influence on the generation of conditional fear responses. Significant increases in amygdala activity were observed during the production of conditioned (learning-related), but not orienting, nonspecific, and unconditioned (nonlearning-related) skin conductance responses. Further, greater amygdala activity was demonstrated during conditioned response production than during conditioned stimulus presentation. These results suggest the amygdala not only responds to fearful stimuli, but also generates learning-related changes in human autonomic fear expression.
NeuroImage, in press
The amygdala plays a central role in the acquisition and expression of fear memories. Laboratory animal studies indicate that the amygdala both receives sensory information and produces learned behavioral and autonomic fear responses. However, prior functional imaging research in humans has largely focused on amygdala activity elicited by fearful stimuli, giving less attention to this region's role in the production of fear responses. In contrast, the present study used functional magnetic resonance imaging to investigate the amygdala's influence on the generation of conditional fear responses. Significant increases in amygdala activity were observed during the production of conditioned (learning-related), but not orienting, nonspecific, and unconditioned (nonlearning-related) skin conductance responses. Further, greater amygdala activity was demonstrated during conditioned response production than during conditioned stimulus presentation. These results suggest the amygdala not only responds to fearful stimuli, but also generates learning-related changes in human autonomic fear expression.
Monday, April 25, 2005
ARTICLE UPDATE - Emotional context during encoding of neutral items modulates brain activation not only during encoding but also during recognition
Susanne Erk, Sonja Martin and Henrik Walter
NeuroImage, in press
In general, encoding of neutral material includes the context in which the respective material is learned. The effect of emotional context on successfully encoded neutral material has been investigated only recently in few studies, but the main underlying mechanisms are still fairly unknown. In the present study, we investigated the effect of positive and negative emotional context on encoding and later recognition of neutral items. We could demonstrate that brain activation not only during encoding but also during recognition of neutral items depended on the emotional valence of the encoding context. Whereas activation of medial temporal lobe structures during encoding specifically predicted subsequent memory when learning appears in a positive emotional context, activation of the anterior temporal cortex in a region with afferent input to the amygdala predicted memory for material learned in negative context. Recognition of items encoded in positive emotional context revealed activation of hippocampal and medial prefrontal regions, recognition of items encoded in negative emotional context revealed activation of the caudate nucleus. We assume that our findings reflect the recruitment of different brain circuits depending on the emotional context during learning.
NeuroImage, in press
In general, encoding of neutral material includes the context in which the respective material is learned. The effect of emotional context on successfully encoded neutral material has been investigated only recently in few studies, but the main underlying mechanisms are still fairly unknown. In the present study, we investigated the effect of positive and negative emotional context on encoding and later recognition of neutral items. We could demonstrate that brain activation not only during encoding but also during recognition of neutral items depended on the emotional valence of the encoding context. Whereas activation of medial temporal lobe structures during encoding specifically predicted subsequent memory when learning appears in a positive emotional context, activation of the anterior temporal cortex in a region with afferent input to the amygdala predicted memory for material learned in negative context. Recognition of items encoded in positive emotional context revealed activation of hippocampal and medial prefrontal regions, recognition of items encoded in negative emotional context revealed activation of the caudate nucleus. We assume that our findings reflect the recruitment of different brain circuits depending on the emotional context during learning.
Friday, April 22, 2005
ARTICLE UPDATE - The Effect of Emotion and Personality on Olfactory Perception
Chen, D. and Dalton, P.
Chemical Senses, 30, 345-351
It is well established that both the emotional tone of sensory stimuli and the personality characteristics of an individual can bias sensory perception. What has largely been unexplored is whether the current emotional state of an individual has a similar effect, and how it works together with other factors. Here we carry out a comprehensive study to examine how olfactory perception is affected by the emotional tone of the stimuli, and the personality and current emotional state of the individual. Subjects reported experiencing happiness, sadness, negativity/hostility and neutrality when exposed to corresponding emotionally themed video clips, and in each case, smelled a suprathreshold pleasant, an unpleasant and a neutral odorant. The time taken for the subject to detect each odorant and the olfactory intensity were recorded. We found that women detected the pleasant odorant faster than the neutral one. In addition, personality modulated reaction time and olfactory intensity, such that neurotic and anxious individuals were selectively biased toward affective rather than neutral odorants. Finally, current emotional state augmented intensity in men but not in women, and differentially influenced the response time. These findings provided new insights into the effects of emotion and personality on olfactory perception.
Chemical Senses, 30, 345-351
It is well established that both the emotional tone of sensory stimuli and the personality characteristics of an individual can bias sensory perception. What has largely been unexplored is whether the current emotional state of an individual has a similar effect, and how it works together with other factors. Here we carry out a comprehensive study to examine how olfactory perception is affected by the emotional tone of the stimuli, and the personality and current emotional state of the individual. Subjects reported experiencing happiness, sadness, negativity/hostility and neutrality when exposed to corresponding emotionally themed video clips, and in each case, smelled a suprathreshold pleasant, an unpleasant and a neutral odorant. The time taken for the subject to detect each odorant and the olfactory intensity were recorded. We found that women detected the pleasant odorant faster than the neutral one. In addition, personality modulated reaction time and olfactory intensity, such that neurotic and anxious individuals were selectively biased toward affective rather than neutral odorants. Finally, current emotional state augmented intensity in men but not in women, and differentially influenced the response time. These findings provided new insights into the effects of emotion and personality on olfactory perception.
Wednesday, April 20, 2005
ARTICLE UPDATE - Emotional and Temporal Aspects of Situation Model Processing during Text Comprehension: An Event-Related fMRI Study
Evelyn C. Ferstl, Mike Rinck and D. Yves von Cramon
Journal of Cognitive Neuroscience, 17, 724-739
Language comprehension in everyday life requires the continuous integration of prior discourse context and general world knowledge with the current utterance or sentence. In the neurolinguistic literature, these so-called situation model building processes have been ascribed to the prefrontal cortex or to the right hemisphere. In this study, we use whole-head event-related fMRI to directly map the neural correlates of narrative comprehension in context. While being scanned using a spin–echo sequence, 20 participants listened to 32 short stories, half of which contained globally inconsistent information. The inconsistencies concerned either temporal or chronological information or the emotional status of the protagonist. Hearing an inconsistent word elicited activation in the right anterior temporal lobe. The comparison of different information aspects revealed activation in the left precuneus and a bilateral frontoparietal network for chronological information. Emotional information elicited activation in the ventromedial prefrontal cortex and the extended amygdaloid complex. In addition, the integration of inconsistent emotional information engaged the dorsal frontomedial cortex (Brodmann's area 8/9), whereas the integration of inconsistent temporal information required the lateral prefrontal cortex bilaterally. These results indicate that listening to stories can elicit activation reflecting content-specific processes. Furthermore, updating of the situation model is not a unitary process but it also depends on the particular requirements of the text. The right hemisphere contributes to language processing in context, but equally important are the left medial and bilateral prefrontal cortices.
Journal of Cognitive Neuroscience, 17, 724-739
Language comprehension in everyday life requires the continuous integration of prior discourse context and general world knowledge with the current utterance or sentence. In the neurolinguistic literature, these so-called situation model building processes have been ascribed to the prefrontal cortex or to the right hemisphere. In this study, we use whole-head event-related fMRI to directly map the neural correlates of narrative comprehension in context. While being scanned using a spin–echo sequence, 20 participants listened to 32 short stories, half of which contained globally inconsistent information. The inconsistencies concerned either temporal or chronological information or the emotional status of the protagonist. Hearing an inconsistent word elicited activation in the right anterior temporal lobe. The comparison of different information aspects revealed activation in the left precuneus and a bilateral frontoparietal network for chronological information. Emotional information elicited activation in the ventromedial prefrontal cortex and the extended amygdaloid complex. In addition, the integration of inconsistent emotional information engaged the dorsal frontomedial cortex (Brodmann's area 8/9), whereas the integration of inconsistent temporal information required the lateral prefrontal cortex bilaterally. These results indicate that listening to stories can elicit activation reflecting content-specific processes. Furthermore, updating of the situation model is not a unitary process but it also depends on the particular requirements of the text. The right hemisphere contributes to language processing in context, but equally important are the left medial and bilateral prefrontal cortices.
Saturday, March 26, 2005
ARTICLE UPDATE - A common neural basis for receptive and expressive communication of pleasant facial affect
Andreas Hennenlotter, Ulrike Schroeder, Peter Erhard, Florian Castrop, Bernhard Haslinger, Daniela Stoecker, Klaus W. Langed and Andres O. Ceballos-Baumann
NeuroImage, in press
There is accumulating evidence suggesting that the visual representation of facial affect is closely linked to its motor representation. To examine whether perception of pleasant facial affect involves neural circuitries associated with its production, we performed an fMRI experiment with ‘compressed image acquisition' where subjects smiled and observed movies depicting other people smiling within scan-free time intervals between the acquisition of each image volume. Overlaps between the brain activation during observation and execution of smile expressions were located in the right premotor cortex and pars opercularis of the inferior frontal gyrus, right parietal operculum (SII) and left anterior insula. Observation of smile expressions further yielded signal increases within the posterior superior temporal sulcus (STS), fusiform gyrus and ventral amygdala. The results show that perceiving and expressing pleasant facial affect share a common neural basis in areas concerned with motor as well as somato- and limbic-sensory processing. In concert with temporal regions serving the visual analysis of facial expressive features, a mapping of the observed expressions onto neural circuitries associated with the production of these expressions and its somatosensory consequences could provide a description of what the expression would feel like if produced in the observer. Such a mechanism is suggested to be important for empathic understanding of others' feelings.
NeuroImage, in press
There is accumulating evidence suggesting that the visual representation of facial affect is closely linked to its motor representation. To examine whether perception of pleasant facial affect involves neural circuitries associated with its production, we performed an fMRI experiment with ‘compressed image acquisition' where subjects smiled and observed movies depicting other people smiling within scan-free time intervals between the acquisition of each image volume. Overlaps between the brain activation during observation and execution of smile expressions were located in the right premotor cortex and pars opercularis of the inferior frontal gyrus, right parietal operculum (SII) and left anterior insula. Observation of smile expressions further yielded signal increases within the posterior superior temporal sulcus (STS), fusiform gyrus and ventral amygdala. The results show that perceiving and expressing pleasant facial affect share a common neural basis in areas concerned with motor as well as somato- and limbic-sensory processing. In concert with temporal regions serving the visual analysis of facial expressive features, a mapping of the observed expressions onto neural circuitries associated with the production of these expressions and its somatosensory consequences could provide a description of what the expression would feel like if produced in the observer. Such a mechanism is suggested to be important for empathic understanding of others' feelings.
Tuesday, March 22, 2005
ARTICLE UPDATE - Contributions of amygdala and striatal activity in emotion regulation
Todd A. Hare, Nim Tottenham, Matthew C. Davidson, Gary H. Glover and B.J. Casey
Biological Psychiatry, 57, 624-632
Background
Emotional information can facilitate or interfere with cognitive processes. In this study, we examined the influence of emotional information in biasing performance and the biological basis underlying this influence.
Methods
Ten human subjects (five female) were scanned with functional magnetic resonance imaging while performing an emotional go/nogo task.
Results
Subjects were slower to approach fearful target expressions and had more difficulty avoiding happy nontarget expressions. The amygdala was recruited most for negative emotional context, and activity in this region was positively correlated with response time when detecting negative expressions. Increased signal in the right caudate nucleus was observed when avoiding nontargets and was negatively correlated with the number of false alarms subjects made.
Conclusions
Emotional context can alter behavioral and biological responses when approaching or avoiding a stimulus. We showed that recruitment of the amygdala, a region implicated in evaluating emotional significance, was associated with longer response latencies when approaching negative information, whereas recruitment of the caudate nucleus, a structure previously implicated in reward and impulse control, was most active when avoiding positive information. Our findings have significant implications for exaggerated and inhibited emotional responses that are characteristic of a number of psychiatric disorders.
Biological Psychiatry, 57, 624-632
Background
Emotional information can facilitate or interfere with cognitive processes. In this study, we examined the influence of emotional information in biasing performance and the biological basis underlying this influence.
Methods
Ten human subjects (five female) were scanned with functional magnetic resonance imaging while performing an emotional go/nogo task.
Results
Subjects were slower to approach fearful target expressions and had more difficulty avoiding happy nontarget expressions. The amygdala was recruited most for negative emotional context, and activity in this region was positively correlated with response time when detecting negative expressions. Increased signal in the right caudate nucleus was observed when avoiding nontargets and was negatively correlated with the number of false alarms subjects made.
Conclusions
Emotional context can alter behavioral and biological responses when approaching or avoiding a stimulus. We showed that recruitment of the amygdala, a region implicated in evaluating emotional significance, was associated with longer response latencies when approaching negative information, whereas recruitment of the caudate nucleus, a structure previously implicated in reward and impulse control, was most active when avoiding positive information. Our findings have significant implications for exaggerated and inhibited emotional responses that are characteristic of a number of psychiatric disorders.
Monday, March 21, 2005
ARTICLE UPDATE - Neuroimaging of emotion: empirical effects of proportional global signal scaling in fMRI data analysis
Markus Junghöfer, Harald T. Schupp, Rudolf Stark and Dieter Vaitl
NeuroImage, 25, 520-526
Global variations of BOLD-fMRI signal are often considered as nuisance effects. This unwanted source of variance is commonly eliminated using proportional global signal scaling (PGSS). However, application of PGSS relies on the assumption that global variations of BOLD signal and experimental conditions are uncorrelated. It has been shown for cognitive tasks that the unjustified application of PGSS might greatly distort statistical results. The present study examined this issue in the domain of emotion research. Specifically, fMRI data were obtained in a block-design, while 21 subjects passively viewed high and low emotionally arousing pleasant, unpleasant, and neutral pictures. Violations of the orthogonality assumption were found for analyses of emotional pictures high in arousal, causing dramatically different outcomes when compared to analyses performed without PGSS. Application of PGSS was associated with attenuated emotional activation in visual cortical areas, insensitivity to emotional activations in limbic and paralimbic regions, and widely distributed artificial deactivations. In contrast, the orthogonality assumption was not violated for low arousing emotional materials. Thus, the validity of using PGSS varied as a function of the emotional arousal of the stimuli. Taken together, the unwarranted use of PGSS might contribute to conflicting results in affective neuroscience fMRI studies, in particular with respect to limbic and paralimbic structures.
NeuroImage, 25, 520-526
Global variations of BOLD-fMRI signal are often considered as nuisance effects. This unwanted source of variance is commonly eliminated using proportional global signal scaling (PGSS). However, application of PGSS relies on the assumption that global variations of BOLD signal and experimental conditions are uncorrelated. It has been shown for cognitive tasks that the unjustified application of PGSS might greatly distort statistical results. The present study examined this issue in the domain of emotion research. Specifically, fMRI data were obtained in a block-design, while 21 subjects passively viewed high and low emotionally arousing pleasant, unpleasant, and neutral pictures. Violations of the orthogonality assumption were found for analyses of emotional pictures high in arousal, causing dramatically different outcomes when compared to analyses performed without PGSS. Application of PGSS was associated with attenuated emotional activation in visual cortical areas, insensitivity to emotional activations in limbic and paralimbic regions, and widely distributed artificial deactivations. In contrast, the orthogonality assumption was not violated for low arousing emotional materials. Thus, the validity of using PGSS varied as a function of the emotional arousal of the stimuli. Taken together, the unwarranted use of PGSS might contribute to conflicting results in affective neuroscience fMRI studies, in particular with respect to limbic and paralimbic structures.
ARTICLE UPDATE - Neural evidence of effects of emotional valence on word recognition
Midori Inaba, Michio Nomura and Hideki Ohira
International Journal of Psychophysiology, in press
There are no clear reports of electrophysiological evidence of the facilitating effect of negative valence on word recognition. However, behavioral psychological studies have suggested that negative words can be recognized more accurately than positive and neutral words. This study aimed to examine whether, and if so how, the valence of words could influence accuracy and event-related potentials (ERPs) in a recognition task. ERPs were recorded from 20 healthy subjects during performance of a word recognition task. We found a behavioral advantage in discriminability between old and new items for negative words. As for ERPs, the positive-going shift was evident for correct responses to targets in late latency at midline and left centro-parietal sites. Additionally, the magnitude of this component was greatest for negative targets, next for positive targets, and least for neutral targets. The findings offer support for the idea that negative content greatly accelerates recognition memory compared to positive and neutral words.
International Journal of Psychophysiology, in press
There are no clear reports of electrophysiological evidence of the facilitating effect of negative valence on word recognition. However, behavioral psychological studies have suggested that negative words can be recognized more accurately than positive and neutral words. This study aimed to examine whether, and if so how, the valence of words could influence accuracy and event-related potentials (ERPs) in a recognition task. ERPs were recorded from 20 healthy subjects during performance of a word recognition task. We found a behavioral advantage in discriminability between old and new items for negative words. As for ERPs, the positive-going shift was evident for correct responses to targets in late latency at midline and left centro-parietal sites. Additionally, the magnitude of this component was greatest for negative targets, next for positive targets, and least for neutral targets. The findings offer support for the idea that negative content greatly accelerates recognition memory compared to positive and neutral words.
Saturday, March 19, 2005
ARTICLE UPDATE - To what extent are emotional visual stimuli processed without attention and awareness?
Pessoa, L.
Current Opinions in Neurobology, in press
In the past few years, important contributions have been made to the study of emotional visual perception. Researchers have reported responses to emotional stimuli in the human amygdala under some unattended conditions (i.e. conditions in which the focus of attention was diverted away from the stimuli due to task instructions), during visual masking and during binocular suppression. Taken together, these results reveal the relative degree of autonomy of emotional processing. At the same time, however, important limitations to the notion of complete automaticity have been revealed. Effects of task context and attention have been shown, as well as large inter-subject differences in sensitivity to the detection of masked fearful faces (whereby briefly presented, target fearful faces are immediately followed by a neutral face that ‘masks’ the initial face). A better understanding of the neural basis of emotional perception and how it relates to visual attention and awareness is likely to require further refinement of the concepts of automaticity and awareness.
Current Opinions in Neurobology, in press
In the past few years, important contributions have been made to the study of emotional visual perception. Researchers have reported responses to emotional stimuli in the human amygdala under some unattended conditions (i.e. conditions in which the focus of attention was diverted away from the stimuli due to task instructions), during visual masking and during binocular suppression. Taken together, these results reveal the relative degree of autonomy of emotional processing. At the same time, however, important limitations to the notion of complete automaticity have been revealed. Effects of task context and attention have been shown, as well as large inter-subject differences in sensitivity to the detection of masked fearful faces (whereby briefly presented, target fearful faces are immediately followed by a neutral face that ‘masks’ the initial face). A better understanding of the neural basis of emotional perception and how it relates to visual attention and awareness is likely to require further refinement of the concepts of automaticity and awareness.
Friday, March 18, 2005
ARTICLE UPDATE - Effects of arousing emotional scenes on the distribution of visuospatial attention: changes with aging and early subcortical vascular
A. Rösler, C. Ulrich, J. Billino, P. Sterzer, S. Weidauer, T. Bernhardt, H. Steinmetz, L. Frölich and A. Kleinschmidt
Journal of the Neurological Sciences, 229-230, 109-116
BACKGROUND: The modulation of attention by emotionally arousing stimuli is highly important for each individual's social function. Disturbances of emotional processing are a supportive feature for the diagnosis of subcortical vascular dementia (SVD). We address here whether these disturbances might be useful as an early disease marker. METHODS: In order to examine the modulation of visual attention by emotionally arousing stimuli of different valence, 12 elderly patients with early SVD, 12 age-comparable healthy adults and 12 young healthy subjects were studied while looking at pairs of pictures from the International Affective Picture Battery that were either neutral-neutral, neutral-positive or neutral-negative in terms of emotional content. Eye movements were recorded with an infrared eye-tracking system. The direction of the first saccade and the dwell time during the 10 s of presentation were measured and compared among groups with parametric tests. RESULTS: All subjects showed a modulation of initial attentional orienting as well as a higher percentage of dwell time towards the pictures containing emotional material. Patients with SVD and old controls did not differ in either experimental measure. Young patients showed a stronger bias towards emotionally negative material than both groups of older individuals. CONCLUSIONS: Modulation of visuospatial attention is preserved in early SVD. This might have implications for therapeutic interventional approaches. A weakened sustained attention towards negative but not positive emotional pictures in the elderly is in accordance with the socioemotional selectivity theory, describing a relative selection of positive stimuli with aging.
Journal of the Neurological Sciences, 229-230, 109-116
BACKGROUND: The modulation of attention by emotionally arousing stimuli is highly important for each individual's social function. Disturbances of emotional processing are a supportive feature for the diagnosis of subcortical vascular dementia (SVD). We address here whether these disturbances might be useful as an early disease marker. METHODS: In order to examine the modulation of visual attention by emotionally arousing stimuli of different valence, 12 elderly patients with early SVD, 12 age-comparable healthy adults and 12 young healthy subjects were studied while looking at pairs of pictures from the International Affective Picture Battery that were either neutral-neutral, neutral-positive or neutral-negative in terms of emotional content. Eye movements were recorded with an infrared eye-tracking system. The direction of the first saccade and the dwell time during the 10 s of presentation were measured and compared among groups with parametric tests. RESULTS: All subjects showed a modulation of initial attentional orienting as well as a higher percentage of dwell time towards the pictures containing emotional material. Patients with SVD and old controls did not differ in either experimental measure. Young patients showed a stronger bias towards emotionally negative material than both groups of older individuals. CONCLUSIONS: Modulation of visuospatial attention is preserved in early SVD. This might have implications for therapeutic interventional approaches. A weakened sustained attention towards negative but not positive emotional pictures in the elderly is in accordance with the socioemotional selectivity theory, describing a relative selection of positive stimuli with aging.
ARTICLE UPDATE - Affective consciousness: Core emotional feelings in animals and humans.
Panksepp J.
Consciousness and Cognition, 14, 30-80
The position advanced in this paper is that the bedrock of emotional feelings is contained within the evolved emotional action apparatus of mammalian brains. This dual-aspect monism approach to brain-mind functions, which asserts that emotional feelings may reflect the neurodynamics of brain systems that generate instinctual emotional behaviors, saves us from various conceptual conundrums. In coarse form, primary process affective consciousness seems to be fundamentally an unconditional "gift of nature" rather than an acquired skill, even though those systems facilitate skill acquisition via various felt reinforcements. Affective consciousness, being a comparatively intrinsic function of the brain, shared homologously by all mammalian species, should be the easiest variant of consciousness to study in animals. This is not to deny that some secondary processes (e.g., awareness of feelings in the generation of behavioral choices) cannot be evaluated in animals with sufficiently clever behavioral learning procedures, as with place-preference procedures and the analysis of changes in learned behaviors after one has induced re-valuation of incentives. Rather, the claim is that a direct neuroscientific study of primary process emotional/affective states is best achieved through the study of the intrinsic ("instinctual"), albeit experientially refined, emotional action tendencies of other animals. In this view, core emotional feelings may reflect the neurodynamic attractor landscapes of a variety of extended trans-diencephalic, limbic emotional action systems-including SEEKING, FEAR, RAGE, LUST, CARE, PANIC, and PLAY. Through a study of these brain systems, the neural infrastructure of human and animal affective consciousness may be revealed. Emotional feelings are instantiated in large-scale neurodynamics that can be most effectively monitored via the ethological analysis of emotional action tendencies and the accompanying brain neurochemical/electrical changes. The intrinsic coherence of such emotional responses is demonstrated by the fact that they can be provoked by electrical and chemical stimulation of specific brain zones-effects that are affectively laden. For substantive progress in this emerging research arena, animal brain researchers need to discuss affective brain functions more openly. Secondary awareness processes, because of their more conditional, contextually situated nature, are more difficult to understand in any neuroscientific detail. In other words, the information-processing brain functions, critical for cognitive consciousness, are harder to study in other animals than the more homologous emotional/motivational affective state functions of the brain.
Consciousness and Cognition, 14, 30-80
The position advanced in this paper is that the bedrock of emotional feelings is contained within the evolved emotional action apparatus of mammalian brains. This dual-aspect monism approach to brain-mind functions, which asserts that emotional feelings may reflect the neurodynamics of brain systems that generate instinctual emotional behaviors, saves us from various conceptual conundrums. In coarse form, primary process affective consciousness seems to be fundamentally an unconditional "gift of nature" rather than an acquired skill, even though those systems facilitate skill acquisition via various felt reinforcements. Affective consciousness, being a comparatively intrinsic function of the brain, shared homologously by all mammalian species, should be the easiest variant of consciousness to study in animals. This is not to deny that some secondary processes (e.g., awareness of feelings in the generation of behavioral choices) cannot be evaluated in animals with sufficiently clever behavioral learning procedures, as with place-preference procedures and the analysis of changes in learned behaviors after one has induced re-valuation of incentives. Rather, the claim is that a direct neuroscientific study of primary process emotional/affective states is best achieved through the study of the intrinsic ("instinctual"), albeit experientially refined, emotional action tendencies of other animals. In this view, core emotional feelings may reflect the neurodynamic attractor landscapes of a variety of extended trans-diencephalic, limbic emotional action systems-including SEEKING, FEAR, RAGE, LUST, CARE, PANIC, and PLAY. Through a study of these brain systems, the neural infrastructure of human and animal affective consciousness may be revealed. Emotional feelings are instantiated in large-scale neurodynamics that can be most effectively monitored via the ethological analysis of emotional action tendencies and the accompanying brain neurochemical/electrical changes. The intrinsic coherence of such emotional responses is demonstrated by the fact that they can be provoked by electrical and chemical stimulation of specific brain zones-effects that are affectively laden. For substantive progress in this emerging research arena, animal brain researchers need to discuss affective brain functions more openly. Secondary awareness processes, because of their more conditional, contextually situated nature, are more difficult to understand in any neuroscientific detail. In other words, the information-processing brain functions, critical for cognitive consciousness, are harder to study in other animals than the more homologous emotional/motivational affective state functions of the brain.
Wednesday, March 16, 2005
new issue of Emotion online now
There are many interesting articles on this issue of "Emotion". The articles are available online now. Duke University has a 4 Telsa scanner... Wow
Tuesday, March 15, 2005
ARTICLE UPDATE - Calling for help is independently modulated by brain systems underlying goal-directed behavior and threat perception
Andrew S. Fox, Terrence R. Oakes, Steven E. Shelton , Alexander K. Converse, Richard J. Davidson, and Ned H. Kalin
PNAS, 102, 4176-4179
In primates, during times of need, calling for help is an universal experience. Calling for help recruits social support and promotes survival. However, calling for help also can attract predators, and it is adaptive to inhibit calls for help when a potential threat is perceived. Based on this, we hypothesized that individual differences in calling for help would be related to the activity of brain systems that mediate goal-directed behavior and the detection of threat. By using high-resolution positron emission tomography in rhesus monkeys undergoing social separation, we demonstrate that increased [18F]-fluoro-2-deoxy-D-glucose uptake in the right dorsolateral prefrontal cortex and decreased uptake in the amygdala independently predict individual differences in calling for help. When taken together, these two regions account for 76% of the variance in calling for help. This result suggests that the drive for affiliation and the perception of threat determine the intensity of an individual's behavior during separation. These findings in monkeys are relevant to humans and provide a conceptual neural framework to understand individual differences in how primates behave when in need of social support.
PNAS, 102, 4176-4179
In primates, during times of need, calling for help is an universal experience. Calling for help recruits social support and promotes survival. However, calling for help also can attract predators, and it is adaptive to inhibit calls for help when a potential threat is perceived. Based on this, we hypothesized that individual differences in calling for help would be related to the activity of brain systems that mediate goal-directed behavior and the detection of threat. By using high-resolution positron emission tomography in rhesus monkeys undergoing social separation, we demonstrate that increased [18F]-fluoro-2-deoxy-D-glucose uptake in the right dorsolateral prefrontal cortex and decreased uptake in the amygdala independently predict individual differences in calling for help. When taken together, these two regions account for 76% of the variance in calling for help. This result suggests that the drive for affiliation and the perception of threat determine the intensity of an individual's behavior during separation. These findings in monkeys are relevant to humans and provide a conceptual neural framework to understand individual differences in how primates behave when in need of social support.
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