Abnormal neural responses to emotional visual stimuli in adolescents with conduct disorder.

BACKGROUND: It is widely held that aggression and antisocial behavior arise as a consequence of a deficiency in responding to emotional cues in the social environment. We asked whether neural responses evoked by affect-laden pictures would be abnormal in adolescents with conduct disorder (CD). METHODS: Functional magnetic resonance imaging during passive viewing of pictures with neutral or strong negative affective valence was performed in 13 male adolescents with severe CD aged 9 to 15 years and in 14 healthy age-matched control subjects. RESULTS: Main effects for negative-neutral affective valence included activations in the amygdala and hippocampus, ventral extrastriate visual cortex, and intraparietal sulcus bilaterally. There was a significant group-by-condition interaction in the right dorsal anterior cingulate cortex that was due to a pronounced deactivation in the patient group during viewing of negative pictures. When correcting for anxiety and depressive symptoms, we additionally found a reduced responsiveness of the left amygdala to negative pictures in patients compared with control subjects. CONCLUSIONS: We suggest that these findings reflect an impairment of both the recognition of emotional stimuli and the cognitive control of emotional behavior in patients with CD, resulting in a propensity for aggressive behavior.     

Brain activity during expectancy of emotional stimuli: an fMRI study

We studied the neural activation associated with the expectancy of emotional stimuli using whole brain fMRI. Fifteen healthy subjects underwent fMRI scanning during which they performed a warned reaction task using emotional pictures carrying pleasant, unpleasant, or neutral content. The task involved an expected or unexpected condition. Data were analyzed by comparing the images acquired under the different conditions. In the expected condition, compared with the unexpected condition, significant activation was observed in the medial, inferior and dorsolateral prefrontal cortex. Whereas the expectancy of pleasant stimuli produced activation in the left dorsolateral and left medial prefrontal cortex as well as in the right cerebellum, the expectancy of unpleasant stimuli produced activation in the right inferior and right medial prefrontal cortex, the right amygdala, the left anterior cingulate cortex, and bilaterally in the visual cortex. These results suggest that the expectancy of emotional stimuli is mediated by the prefrontal area including the medial, inferior, and dorsolateral prefrontal cortex. Furthermore, our data suggest that left frontal activation is associated with the expectancy of pleasant stimuli and that right frontal activation is associated with the expectancy of unpleasant stimuli. Finally, our findings suggest that the amygdala and anterior cingulate cortex may play an important role in the expectancy of unpleasant stimuli and that the input of this negative information is modulated by these specific brain areas.     

Anterior cingulate cortex modulates preparatory activation during certain anticipation of negative picture

We studied the neural activation associated with anticipations of emotional pictures using functional magnetic resonance imaging (fMRI) by directly comparing certain with uncertain anticipation conditions. While being scanned with fMRI, healthy participants (n=18) were cued to anticipate and then perceive emotional stimuli having predictable (i.e., certain) emotional valences (i.e., positive and negative), given a preceding cue, as well as cued stimuli of uncertain valence (positive or negative). During anticipation of pictures with certain negative valence, activities of supracallosal anterior cingulate cortex, ventrolateral prefrontal cortex, insula, and amygdala were enhanced relative activity levels that for the uncertain emotional anticipation condition. This result suggests that these brain regions are involved in anticipation of negative images, and that their activity levels may be enhanced by the certainty of anticipation. Furthermore, the supracallosal anterior cingulate cortex showed functional connectivity with the insula, prefrontal cortex, and occipital cortex during the certain negative anticipation. These findings are consistent with an interpretation that top-down modulation, arising from anterior brain regions, is engaged in certain negative anticipation within the occipital cortex. It is thought that the limbic system involving the amygdala, ACC, and insula, engaged emotional processes, and that the input system involving the visual cortex entered an idling state.     

The neural correlates of sex differences in emotional reactivity and emotion regulation

Sex differences in emotional responding have been repeatedly postulated but less consistently shown in empirical studies. Because emotional reactions are modulated by cognitive appraisal, sex differences in emotional responding might depend on differences in emotion regulation. In this study, we investigated sex differences in emotional reactivity and emotion regulation using a delayed cognitive reappraisal paradigm and measured whole‐brain BOLD signal in 17 men and 16 women. During fMRI, participants were instructed to increase, decrease, or maintain their emotional reactions evoked by negative pictures in terms of cognitive reappraisal. We analyzed BOLD responses to aversive compared to neutral pictures in the initial viewing phase and the effect of cognitive reappraisal in the subsequent regulation phase. Women showed enhanced amygdala responding to aversive stimuli in the initial viewing phase, together with increased activity in small clusters within the prefrontal cortex and the temporal cortex. During cognitively decreasing emotional reactions, women recruited parts of the orbitofrontal cortex, the anterior cingulate, and the dorsolateral prefrontal cortex to a lesser extent than men, while there was no sex effect on amygdala activity. In contrast, compared to women, men showed an increased recruitment of regulatory cortical areas during cognitively increasing initial emotional reactions, which was associated with an increase in amygdala activity. Clinical implications of these findings are discussed. Hum Brain Mapp, 2010. © 2009 Wiley‐Liss, Inc.     

Emotionally negative stimuli can overcome attentional deficits in patients with visuo-spatial hemineglect

Left unilateral spatial neglect resulting from right brain damage is characterized by loss of awareness for stimuli in the contralesional side of space, despite intact visual pathways. We examined using fMRI whether patients with neglect are more likely to consciously detect in the neglected hemifield, emotionally negative complex scenes rather than visually similar neutral pictures and if so, what neural mechanisms mediate this effect. Photographs of emotional and neutral scenes taken from the IAPS were presented in a divided visual field paradigm. As expected, the detection rate for emotional stimuli presented in the neglected field was higher than for neutral ones. Successful detection of emotional scenes as opposed to neutral stimuli in the left visual field (LVF) produced activations in the parahippocampal and anterior cingulate areas in the right hemisphere. Detection of emotional stimuli presented in the intact right visual field (RVF) activated a distributed network of structures in the left hemisphere, including anterior and posterior cingulate cortex, insula, as well as visual striate and extrastriate areas. LVF-RVF contrasts for emotional stimuli revealed activations in right and left attention related prefrontal areas whereas RVF-LVF comparison showed activations in the posterior cingulate and extrastriate visual cortex in the left hemisphere. An additional analysis contrasting detected vs. undetected emotional LVF stimuli showed involvement of left anterior cingulate, right frontal and extrastriate areas. We hypothesize that beneficial role of emotion in overcoming neglect is achieved by activation of frontal and limbic lobe networks, which provide a privileged access of emotional stimuli to attention by top-down modulation of processing in the higher-order extrastriate visual areas. Our results point to the importance of top-down regulatory role of the frontal attentional systems, which might enhance visual activations and lead to greater salience of emotional stimuli for perceptual awareness.     

Neural substrates for voluntary suppression of negative affect: a functional magnetic resonance imaging study.

BACKGROUND: Successful control of affect partly depends on the capacity to modulate negative emotional responses through the use of cognitive strategies. Although the capacity to regulate emotions is critical to mental well-being, its neural substrates remain unclear. METHODS: We used functional magnetic resonance imaging to ascertain brain regions involved in the voluntary regulation of emotion and whether dynamic changes in negative emotional experience can modulate their activation. Fourteen healthy subjects were scanned while they either maintained the negative affect evoked by highly arousing and aversive pictures (e.g., experience naturally) or suppressed their affect using cognitive reappraisal. In addition to a condition-based analysis, online subjective ratings of intensity of negative affect were used as covariates of brain activity. RESULTS: Inhibition of negative affect was associated with activation of dorsal anterior cingulate, dorsal medial prefrontal, and lateral prefrontal cortices, and attenuation of brain activity within limbic regions (e.g., nucleus accumbens/extended amygdala). Furthermore, activity within dorsal anterior cingulate was inversely related to intensity of negative affect, whereas activation of the amygdala was positively covaried with increasing negative affect. CONCLUSIONS: These findings highlight a functional dissociation of corticolimbic brain responses, involving enhanced activation of prefrontal cortex and attenuation of limbic areas, during volitional suppression of negative emotion.     

Us versus them: Political attitudes and party affiliation influence neural response to faces of presidential candidates

We investigated how political party affiliation and political attitudes modulate neural activity while viewing faces of presidential candidates. Ten registered Democrats and 10 registered Republicans were scanned in an event-related functional MRI paradigm while viewing pictures of the faces of George Bush, John Kerry, and Ralph Nader during the 2004 United States presidential campaign. We found that compared with viewing one's own candidate, viewing the candidate from the opposing political party produced signal changes in cognitive control circuitry in the dorsolateral prefrontal cortex and anterior cingulate, as well as in emotional regions such as the insula and anterior temporal poles. BOLD signal in these regions correlated with subjects' self-reported ratings of how they felt emotionally about the candidates. These data suggest that brain activity when viewing a politician's face is affected by the political allegiance of the viewer and that people regulate their emotional reactions to opposing candidates by activating cognitive control networks.     

Neural correlates of the affect regulation model in schizophrenia patients with substance use history: a functional magnetic resonance imaging study

BACKGROUND: The lifetime prevalence of substance use disorders among schizophrenia patients is close to 50%. The negative consequences of substance abuse in schizophrenia are well documented, but the etiology of this comorbid condition remains unknown. According to the affect regulation model, schizophrenia patients abuse drugs in order to cope with their negative affects. Supporting the model, clinical studies have shown that dual-diagnosis patients have less blunting of affect and that they experience more negative affect. We hypothesized that patients with a history of substance use would have increased cerebral activations in response to aversive stimuli when compared to abstinent patients. METHOD: Schizophrenia patients were divided into 2 groups: patients with (SCZ-SU group; N = 12) and without (SCZ group; N = 11) a current or past substance use disorder (alcohol, cannabis, and/or LSD). Diagnoses were made according to DSM-IV criteria. Using functional magnetic resonance imaging (fMRI), patients were scanned during passive viewing of emotionally negative pictures (International Affective Picture System). Data were gathered from September 2001 to December 2003. RESULTS: Subjectively, the emotional experience induced by viewing the negative pictures was rated significantly higher in the SCZ-SU group than in the SCZ group (p = .008). Neurally, in the SCZ-SU group, significant loci of activation were identified in the right medial prefrontal cortex (Brodmann's area [BA] 10), left medial prefrontal cortex (BA 10), right orbitofrontal cortex (BA 47), and left amygdala. No significant loci of activation were observed in the SCZ group. CONCLUSIONS: These results suggest that the functioning of the medial prefrontal cortex, thought to be impaired in patients with prominent negative symptoms, is more preserved in dual-diagnosis schizophrenia. This relative preservation could be primary or secondary to substance use.     

Brain activation during the perception of stressful word stimuli concerning interpersonal relationships in anorexia nervosa patients with high degrees of alexithymia in an fMRI paradigm

Several studies have reported that anorexia nervosa (AN) patients have high levels of alexithymia. However, relatively little is known about the underlying neurobiological relationships between alexithymia and AN. We used functional magnetic resonance imaging to examine the brain responses in 30 AN patients and 20 healthy women during the processing of negative words concerning interpersonal relationships. We investigated the relationship between alexithymia levels and brain activation in AN. AN patients showed significant activation of the orbitofrontal cortex, dorsolateral prefrontal cortex and medial prefrontal cortex while processing negative words concerning interpersonal relationships, as compared to the processing of neutral words. Moreover, the subjective rating of unpleasantness with negative words and neural activities in the amygdala, posterior cingulate cortex (PCC) and anterior cingulate cortex (ACC) negatively correlated with the level of alexithymia in AN. Our neuroimaging results suggest that AN patients tend to cognitively process negative words concerning interpersonal relationships, resulting in activation of the prefrontal cortex. Lower activation of the amygdala, PCC and ACC in response to these words may contribute to the impairments of emotional processing that are hallmarks of alexithymia. Functional abnormalities associated with alexithymia may be involved in the emotional processing impairments in AN patients.     

The neural basis of romantic love

The neural correlates of many emotional states have been studied, most recently through the technique of fMRI. However, nothing is known about the neural substrates involved in evoking one of the most overwhelming of all affective states, that of romantic love, about which we report here. The activity in the brains of 17 subjects who were deeply in love was scanned using fMRI, while they viewed pictures of their partners, and compared with the activity produced by viewing pictures of three friends of similar age, sex and duration of friendship as their partners. The activity was restricted to foci in the medial insula and the anterior cingulate cortex and, subcortically, in the caudate nucleus and the putamen, all bilaterally. Deactivations were observed in the posterior cingulate gyrus and in the amygdala and were right-lateralized in the prefrontal, parietal and middle temporal cortices. The combination of these sites differs from those in previous studies of emotion, suggesting that a unique network of areas is responsible for evoking this affective state. This leads us to postulate that the principle of functional specialization in the cortex applies to affective states as well.     

Interaction among childhood trauma and functional polymorphisms in the serotonin pathway moderate the risk of depressive disorders

Borderline personality disorder (BPD) is associated with disturbed emotion processing, typically encompassing intense and fast emotional reactions toward affective stimuli. In this study, we were interested in whether emotional dysregulation in BPD occurs not only during the perception of emotional stimuli, but also during the anticipation of upcoming emotional pictures in the absence of concrete stimuli. Eighteen female patients with a diagnosis of BPD and 18 healthy control subjects anticipated cued visual stimuli with prior known emotional valence or prior unknown emotional content during functional magnetic resonance imaging. Brain activity during the anticipation of emotional stimuli was compared between both groups. When anticipating negative pictures, BPD patients demonstrated less signal change in the left dorsal anterior cingulate cortex (dACC) and left middle cingulate cortex (MCC), and enhanced activations in the left pregenual ACC, left posterior cingulate cortex (PCC) as well as in left visual cortical areas including the lingual gyrus. During the anticipation of ambiguously announced stimuli, brain activity in BPD was also reduced in the left MCC extending into the medial and bilateral dorsolateral prefrontal cortex. Results point out that deficient recruitment of brain areas related to cognitive–emotional interaction already during the anticipation phase may add to emotional dysregulation in BPD. Stronger activation of the PCC could correspond to an increased autobiographical reference in BPD. Moreover, increased preparatory visual activity during negative anticipation may contribute to hypersensitivity toward emotional cues in this disorder.     

The emotional modulation of cognitive processing: an fMRI study

The functional neuroanatomy of visual processing of surface features of emotionally valenced pictorial stimuli was examined in normal human subjects using functional magnetic resonance imaging (fMRI). Pictorial stimuli were of two types: emotionally negative and neutral pictures. Task performance was slower for the negatively valenced than for the neutral pictures. Significant blood oxygen level dependent (BOLD) increases occurred in the medial and dorsolateral prefrontal cortex, midbrain, substantia innominata, and/or amygdala, and in the posterior cortical visual areas for both stimulus types. Increases were greater for the negatively valenced stimuli. While there was a small but significant BOLD decrease in the subgenual prefrontal cortex, which was larger in response to the negatively valenced pictures, there was an almost complete absence of other decreases prominently seen during the performance of demanding cognitive tasks [Shulman, G. L., Fiez, J. A., Corbetta, M., Buckner, R. L., Miezin, F. M., Raichle, M. E., & Petersen, S. E. (1997). Common blood flow changes across visual tasks: II. Decreases in cerebral cortex. Journal of Cognitive Neuroscience, 9, 648--663]. These results provide evidence that the emotional valence and arousing nature of stimuli used during the performance of an attention-demanding cognitive task are reflected in discernable, quantitative changes in the functional anatomy associated with task performance.     

Brain activation during direct and indirect processing of positive and negative words

The effects of task conditions on brain activation to emotional stimuli are poorly understood. In this event-related fMRI study, brain activation to negative and positive words (matched for arousal) and neutral words was investigated under two task conditions. Subjects either had to attend to the emotional meaning (direct task) or to non-emotional features of the words (indirect task). Regardless of task, positive vs. negative words led to increased activation in the ventral medial prefrontal cortex, while negative vs. positive words induced increased activation of the insula. Compared to neutral words, all emotional words were associated with increased activation of the amygdala. Finally, the direct condition, as compared to the indirect condition, led to enhanced activation to emotional vs. neutral words in the dorsomedial prefrontal cortex and the anterior cingulate cortex. These results suggest valence and arousal dependent brain activation patterns that are partially modulated by participants’ processing mode of the emotional stimuli.     

Paralimbic and medial prefrontal cortical involvement in neuroendocrine responses to traumatic stimuli

OBJECTIVE: Hypothalamic-pituitary-adrenal axis activity and cortisol release are consequences of central stress system activation, but they may also influence cognitive and emotional processes within the brain. Despite the importance of central stress response systems, little is known about the specific brain circuits through which psychosocial stimuli activate the hypothalamic-pituitary-adrenal axis and through which cortisol feedback modulates central processing. The authors used [(15)O]H(2)O positron emission tomography (PET) on subjects with posttraumatic stress disorder (PTSD) to study these circuits. METHOD: Participants were combat-PTSD patients, combat-exposed healthy comparison subjects, and noncombat-exposed healthy comparison subjects. Participants were scanned using [(15)O]H(2)O PET while they experienced a series of emotional-induction conditions, which included aversive pictures and autobiographic narratives. Blood samples were obtained 2 minutes before and 5 minutes after each activation scan in order to measure the subjects' plasma adrenocorticotropic hormone and cortisol levels. RESULTS: In voxel-wise analyses, the authors found that adrenocorticotropic hormone responses were covaried with regional cerebral blood flow (rCBF) in the dorsal medial prefrontal cortex, rostral anterior cingulate cortex, and right insula, with some differences between PTSD patients and comparison subjects. Prestimulus cortisol levels covaried with rCBF responses in the rostral anterior cingulate cortex. In combat-PTSD patients only, prestimulus cortisol levels covaried with rCBF in the subgenual anterior cingulate cortex. CONCLUSIONS: These findings provide evidence of cortical involvement in hypothalamic-pituitary-adrenal responses to psychological stimuli, specifically implicating the insula, dorsal medial prefrontal cortex, and rostral anterior cingulate cortex. These findings also show, for the first time, that cortisol may modulate activity in specific brain areas such as the rostral and subgenual anterior cingulate cortices. Differential patterns of covariation between combat veterans with and without PTSD potentially implicate the dorsal medial prefrontal cortex and subgenual anterior cingulate cortex as areas of dysregulation in PTSD.     

Medial prefrontal cortex activity during memory encoding of pictures and its relation to symptomatic improvement after citalopram treatment in patients with major depression

Background

Brain imaging studies of major depressive disorder have shown alterations in the brain regions typically involved in episodic memory, including the prefrontal cortex and medial temporal areas. Some studies of major depressive disorder have linked episodic memory performance to treatment response. In this study, we sought to identify brain regions whose activity, measured during the encoding of pictures, predicted symptomatic improvement after 8 weeks of citalopram treatment.

Methods

We included 20 unmedicated depressed patients. These patients performed an episodic recognition memory task during functional magnetic resonance imaging. During the encoding phase, 150 pictures depicting emotionally positive, negative or neutral content were presented, and the participants were required to classify each picture according to its emotional valence. The same 150 pictures were presented, along with 150 new ones, for a recognition task. We asked participants to distinguish the old pictures from the new ones. We assessed symptom severity by use of the 21-item Hamilton Rating Scale for Depression (HAM-D) at baseline and after 8 weeks of citalopram treatment. We performed subsequent memory effect analyses using SPM2 software. We explored the relation between brain activation during successful encoding of pictures and symptomatic improvement.

Results

Patients showed a mean symptomatic improvement of 54.5% on the HAM-D after 8 weeks. Symptomatic improvement was significantly and positively correlated with picture recognition memory accuracy. We also found that the activity of the ventromedial prefrontal cortex and anterior cingulate cortex during successful encoding was significantly correlated with symptomatic improvement. Finally, we found greater activation in the ventromedial prefrontal cortex during the successful encoding of positive pictures in comparison with neutral pictures.

Limitations

During the recognition memory task, 5 participants (among the best responders to treatment) were not included in the valence-specific analyses because they had very few errors. A more challenging task would have allowed the inclusion of most patients.

Conclusion

Different types of functional imaging paradigms have been used to explore whether the activity of specific brain regions measured at baseline is predictive of a better response to treatment in major depressive disorder. Among these regions, the medial prefrontal cortex and anterior cingulate cortex usually show the strongest predictive value. According to our results, the medial prefrontal cortex and anterior cingulate cortex could have an effect on treatment response in major depressive disorder by contributing to the successful encoding of positively valenced information.     

Neural correlates of sad feelings in schizophrenia with and without blunted affect.

OBJECTIVE: There have been reports that patients with schizophrenia have decreased activity in the prefrontal cortex during emotion processing. However, findings have been confounded by sample nonspecificity and explicit cognitive task interference with emotion processing. We aimed to further investigate this by examining the ventrolateral prefrontal cortex (VLPFC) activation in response to the passive viewing of sad film excerpts. METHODS: We presented film excerpts depicting sad and neutral social situations to 25 schizophrenia patients (14 with blunted affect [BA+] and 11 without blunted affect [BA-]) in an implicit perception task to evoke prefronto-limbic activity illustrated by blood oxygenation level-dependent functional magnetic resonance imaging. RESULTS: A random-effects analysis (2-sample t test) using statistical parametric mapping indicated that BA+ patients differed from BA- patients at a 0.05 level (P corrected for multiple comparisons). Consistent with our a priori hypothesis, BA- patients (relative to BA+ patients) showed significant activation in the right VLPFC. An exploratory analysis revealed the following loci of activation: caudate nucleus, VLPFC, middle prefrontal cortex, medial prefrontal cortex, anterior cingulate cortex, and anterior temporal pole in the BA- group; and hippocampus, cerebellum, anterior temporal pole, and midbrain in the BA+ group. CONCLUSIONS: We observed not only hypofrontality in the BA+ group but also dysfunctional circuitry distributed throughout the brain. The temporal and midbrain activation seen in the BA+ group may indicate that these brain regions were working harder to compensate for inactivation in other regions. These distributed dysfunctional circuits may form the neural basis of blunted affect through impairment of emotion processing in the brain that prevents it from processing input efficiently and producing output effectively, thereby leading to symptoms such as blunted affect.     

Cognitive generation of affect in bipolar depression: an fMRI study

Individuals with bipolar disorder manifest the full spectrum of emotions ranging from depression to mania. In attempting to understand the functional substrates of mood we attempted to identify brain regions associated with the cognitive generation of affect in bipolar depressed patients. We therefore examined ten depressed female subjects with bipolar affective disorder, and ten age-matched and sex-matched healthy comparison subjects using functional magnetic resonance imaging (fMRI) while viewing alternating blocks of captioned pictures designed to evoke negative, positive or no affective change. The activation paradigm involved the presentation of the same visual materials over three experiments alternating (experiment 1) negative and reference; (experiment 2) positive and reference and (experiment 3) positive and negative captioned pictures. The stimuli produced activation in both patients and comparison subjects in brain regions previously implicated in the generation and modulation of affect, in particular the prefrontal and anterior cingulate cortices. The activation in patients, when compared with healthy subjects, involved additional subcortical regions, in particular the amygdala, thalamus, hypothalamus and medial globus pallidus. Patients and comparison subjects displayed differential sensitivity to affective change with negative (experiment 1) and positive (experiment 2) affect induction producing converse patterns of activation. We conclude that bipolar depressed patients perhaps recruit additional subcortical limbic systems for emotional evaluation and this may reflect state-related or trait-related dysfunction. The differential patterns of activation inform us about bipolar depression and have potential diagnostic and therapeutic significance.     

An affective circumplex model of neural systems subserving valence, arousal, and cognitive overlay during the appraisal of emotional faces

Increasing evidence supports the existence of distinct neural systems that subserve two dimensions of affect--arousal and valence. Ten adult participants underwent functional magnetic resonance imaging during which they were presented a range of standardized faces and then asked, during the scan, to rate the emotional expressions of the faces along the dimensions of arousal and valence. Lower ratings of arousal accompanied greater activity in the amygdala complex, cerebellum, dorsal pons, and right medial prefrontal cortex (mPFC). More negative ratings of valence accompanied greater activity in the dorsal anterior cingulate (dACC) and parietal cortices. Extreme ratings of valence (highly positive and highly negative ratings) accompanied greater activity in the temporal cortex and fusiform gyrus. Building on an empirical literature which suggests that the amygdala serves as a salience and ambiguity detector, we interpret our findings as showing that a face rated as having low arousal is more ambiguous and a face rated as having extreme valence is more personally salient. This explains how both low arousal and extreme valence lead to greater activation of an ambiguity/salience system subserved by the amygdala, cerebellum, and dorsal pons. In addition, the right medial prefrontal cortex appears to down-regulate individual ratings of arousal, whereas the fusiform and related temporal cortices seem to up-regulate individual assessments of extreme valence when individual ratings are studied relative to group reference ratings for each stimulus. The simultaneous assessment of the effects of arousal and valence proved essential for the identification of neural systems contributing to the processing of emotional faces.     

Neural activity associated with episodic memory for emotional context

To address the question of which brain regions subserve retrieval of emotionally-valenced memories, we used event-related fMRI to index neural activity during the incidental retrieval of emotional and non-emotional contextual information. At study, emotionally neutral words were presented in the context of sentences that were either negatively, neutrally or positively valenced. At test, fMRI data were obtained while participants discriminated between studied and unstudied words. Recognition of words presented in emotionally negative relative to emotionally neutral contexts was associated with enhanced activity in right dorsolateral prefrontal cortex, left amygdala and hippocampus, right lingual gyrus and posterior cingulate cortex. Recognition of words from positive relative to neutral contexts was associated with increased activity in bilateral prefrontal and orbitofrontal cortices, and left anterior temporal lobe. These findings suggest that neural activity mediating episodic retrieval of contextual information and its subsequent processing is modulated by emotion in at least two ways. First, there is enhancement of activity in networks supporting episodic retrieval of neutral information. Second, regions known to be activated when emotional information is encountered in the environment are also active when emotional information is retrieved from memory.     

Amygdala-frontal connectivity during emotion regulation

Successful control of affect partly depends on the capacityto modulate negative emotional responses through the use ofcognitive strategies (i.e., reappraisal). Recent studies suggestthe involvement of frontal cortical regions in the modulationof amygdala reactivity and the mediation of effective emotionregulation. However, within-subject inter-regional connectivitybetween amygdala and prefrontal cortex in the context of affectregulation is unknown. Here, using psychophysiological interactionanalyses of functional magnetic resonance imaging data, we showthat activity in specific areas of the frontal cortex (dorsolateral,dorsal medial, anterior cingulate, orbital) covaries with amygdalaactivity and that this functional connectivity is dependenton the reappraisal task. Moreover, strength of amygdala couplingwith orbitofrontal cortex and dorsal medial prefrontal cortexpredicts the extent of attenuation of negative affect followingreappraisal. These findings highlight the importance of functionalconnectivity within limbic-frontal circuitry during emotionregulation.