Atypical modulation of medial prefrontal cortex to self-referential comments in generalized social phobia

On the role of the ventromedial prefrontal cortex in self-processing: the valuation hypothesis

With the development of functional neuroimaging, important progress has been made in identifying the brain regions involved in self-related processing. One of the most consistent findings has been that the ventromedial prefrontal cortex (vMPFC) is activated when people contemplate various aspects of themselves and their life, such their traits, experiences, preferences, abilities, and goals. Recent evidence suggests that this region may not support the act of self-reflection per se, but its precise function in self-processing remains unclear. In this article, I examine the hypothesis that the vMPFC may contribute to assign personal value or significance to self-related contents: stimuli and mental representations that refer or relate to the self tend to be assigned unique value or significance, and the function of the vMPFC may precisely be to evaluate or represent such significance. Although relatively few studies to date have directly tested this hypothesis, several lines of evidence converge to suggest that vMPFC activity during self-processing depends on the personal significance of self-related contents. First, increasing psychological distance from self-representations leads to decreased activation in the vMPFC. Second, the magnitude of vMPFC activation increases linearly with the personal importance attributed to self-representations. Third, the activity of the vMPFC is modulated by individual differences in the interest placed on self-reflection. Finally, the evidence shows that the vMPFC responds to outer aspects of self that have high personal value, such as possessions and close others. By assigning personal value to self-related contents, the vMPFC may play an important role in the construction, stabilization, and modification of self-representations, and ultimately in guiding our choices and decisions.

General emotion processing in social anxiety disorder: neural issues of cognitive control

Anxiety disorders are characterized by deficient emotion regulation prior to and in anxiety-evoking situations. Patients with social anxiety disorder (SAD) have increased brain activation also during the anticipation and perception of non-specific emotional stimuli pointing to biased general emotion processing. In the current study we addressed the neural correlates of emotion regulation by cognitive control during the anticipation and perception of non-specific emotional stimuli in patients with SAD. Thirty-two patients with SAD underwent functional magnetic resonance imaging during the announced anticipation and perception of emotional stimuli. Half of them were trained and instructed to apply reality-checking as a control strategy, the others anticipated and perceived the stimuli. Reality checking significantly (p<0.01) reduced activity in insular, amygdalar and medial thalamic areas during the anticipation and perception of negative emotional stimuli. The medial prefrontal cortex was comparably active in both groups (p>0.50). The results suggest that cognitive control in patients with SAD influences emotion processing structures, supporting the usefulness of emotion regulation training in the psychotherapy of SAD. In contrast to studies in healthy subjects, cognitive control was not associated with increased activation of prefrontal regions in SAD. This points to possibly disturbed general emotion regulating circuits in SAD.

Neural response to the observable self in social anxiety disorder

BACKGROUND

Distorted images of the observable self are considered crucial in the development and maintenance of social anxiety. We generated an experimental situation in which participants viewed themselves from an observer's perspective when exposed to scrutiny and evaluation by others. Method Twenty patients with social anxiety disorder (SAD) and 20 control subjects were assessed using functional magnetic resonance imaging (fMRI) during the public exposure of pre-recorded videos in which they were each shown performing a verbal task. The examiners acted as the audience in the experiment and rated performance. Whole-brain functional maps were computed using Statistical Parametric Mapping.

RESULTS

Robust activation was observed in regions related to self-face recognition, emotional response and general arousal in both study groups. Patients showed significantly greater activation only in the primary visual cortex. By contrast, they showed significant deactivation or smaller activation in dorsal frontoparietal and anterior cingulate cortices relevant to the cognitive control of negative emotion. Task-related anxiety ratings revealed a pattern of negative correlation with activation in this frontoparietal/cingulate network. Importantly, the relationship between social anxiety scores and neural response showed an inverted-U function with positive correlations in the lower score range and negative correlations in the higher range.

CONCLUSIONS

Our findings suggest that exposure to scrutiny and evaluation in SAD may be associated with changes in cortical systems mediating the cognitive components of anxiety. Disorder severity seems to be relevant in shaping the neural response pattern, which is distinctively characterized by a reduced cortical response in the most severe cases.

Is there less to social anxiety than meets the eye? Behavioral and neural responses to three socio-emotional tasks

Background

Social anxiety disorder (SAD) is widely thought to be characterized by heightened behavioral and limbic reactivity to socio-emotional stimuli. However, although behavioral findings are clear, neural findings are surprisingly mixed.

Methods

Using functional magnetic resonance imaging (fMRI), we examined behavioral and brain responses in a priori emotion generative regions of interest (amygdala and insula) in 67 patients with generalized SAD and in 28 healthy controls (HC) during three distinct socio-emotional tasks. We administered these socio-emotional tasks during one fMRI scanning session: 1) looming harsh faces (Faces); 2) videotaped actors delivering social criticism (Criticism); and 3) written negative self-beliefs (Beliefs).

Results

In each task, SAD patients reported heightened negative emotion, compared to HC. There were, however, no SAD versus HC differential brain responses in the amygdala and insula. Between-group whole-brain analyses confirmed no group differences in the responses of the amygdala and insula, and indicated different brain networks activated during each of the tasks. In SAD participants, social anxiety symptom severity was associated with increased BOLD signal in the left insula during the Faces task.

Conclusions

The similar responses in amygdala and insula in SAD and HC participants suggest that heightened negative emotion responses reported by patients with SAD may be related to dysfunction in higher cognitive processes (e.g., distorted appraisal, attention biases, or ineffective cognitive reappraisal). In addition, the findings of this study emphasize the differential effects of socio-emotional experimental tasks.

Functional magnetic resonance imaging during emotion recognition in social anxiety disorder: an activation likelihood meta-analysis

Background: Social anxiety disorder (SAD) is characterized by abnormal fear and anxiety in social situations. Functional magnetic resonance imaging (fMRI) is a brain imaging technique that can be used to demonstrate neural activation to emotionally salient stimuli. However, no attempt has yet been made to statistically collate fMRI studies of brain activation, using the activation likelihood-estimate (ALE) technique, in response to emotion recognition tasks in individuals with SAD. Methods: A systematic search of fMRI studies of neural responses to socially emotive cues in SAD was undertaken. ALE meta-analysis, a voxel-based meta-analytic technique, was used to estimate the most significant activations during emotional recognition. Results: Seven studies were eligible for inclusion in the meta-analysis, constituting a total of 91 subjects with SAD, and 93 healthy controls. The most significant areas of activation during emotional vs. neutral stimuli in individuals with SAD compared to controls were: bilateral amygdala, left medial temporal lobe encompassing the entorhinal cortex, left medial aspect of the inferior temporal lobe encompassing perirhinal cortex and parahippocampus, right anterior cingulate, right globus pallidus, and distal tip of right postcentral gyrus. Conclusion: The results are consistent with neuroanatomic models of the role of the amygdala in fear conditioning, and the importance of the limbic circuitry in mediating anxiety symptoms.

Recent advances in the brain imaging of social anxiety disorder

Social anxiety disorder (SAD) is one of the most common and disabling anxiety disorders, yet much remains to be learned about its psychobiology. Although functional imaging has emphasized the role of the amygdala and other limbic structures in the neurobiology of SAD, structural and connectivity imaging techniques have emphasized the possibility of abnormalities in other regions and in whole-brain networks. The involvement of a broad range of networks in SAD is consistent with current understandings of the neuroanatomy of emotion and of social processing.

On the role of the ventromedial prefrontal cortex in self-processing: the valuation hypothesis

With the development of functional neuroimaging, important progress has been made in identifying the brain regions involved in self-related processing. One of the most consistent findings has been that the ventromedial prefrontal cortex (vMPFC) is activated when people contemplate various aspects of themselves and their life, such their traits, experiences, preferences, abilities, and goals. Recent evidence suggests that this region may not support the act of self-reflection per se, but its precise function in self-processing remains unclear. In this article, I examine the hypothesis that the vMPFC may contribute to assign personal value or significance to self-related contents: stimuli and mental representations that refer or relate to the self tend to be assigned unique value or significance, and the function of the vMPFC may precisely be to evaluate or represent such significance. Although relatively few studies to date have directly tested this hypothesis, several lines of evidence converge to suggest that vMPFC activity during self-processing depends on the personal significance of self-related contents. First, increasing psychological distance from self-representations leads to decreased activation in the vMPFC. Second, the magnitude of vMPFC activation increases linearly with the personal importance attributed to self-representations. Third, the activity of the vMPFC is modulated by individual differences in the interest placed on self-reflection. Finally, the evidence shows that the vMPFC responds to outer aspects of self that have high personal value, such as possessions and close others. By assigning personal value to self-related contents, the vMPFC may play an important role in the construction, stabilization, and modification of self-representations, and ultimately in guiding our choices and decisions.

Randomized controlled trial of mindfulness-based stress reduction versus aerobic exercise: effects on the self-referential brain network in social anxiety disorder

Background: Social anxiety disorder (SAD) is characterized by distorted self-views. The goal of this study was to examine whether mindfulness-based stress reduction (MBSR) alters behavioral and brain measures of negative and positive self-views. Methods: Fifty-six adult patients with generalized SAD were randomly assigned to MBSR or a comparison aerobic exercise (AE) program. A self-referential encoding task was administered at baseline and post-intervention to examine changes in behavioral and neural responses in the self-referential brain network during functional magnetic resonance imaging. Patients were cued to decide whether positive and negative social trait adjectives were self-descriptive or in upper case font. Results: Behaviorally, compared to AE, MBSR produced greater decreases in negative self-views, and equivalent increases in positive self-views. Neurally, during negative self versus case, compared to AE, MBSR led to increased brain responses in the posterior cingulate cortex (PCC). There were no differential changes for positive self versus case. Secondary analyses showed that changes in endorsement of negative and positive self-views were associated with decreased social anxiety symptom severity for MBSR, but not AE. Additionally, MBSR-related increases in dorsomedial prefrontal cortex (DMPFC) activity during negative self-view versus case were associated with decreased social anxiety related disability and increased mindfulness. Analysis of neural temporal dynamics revealed MBSR-related changes in the timing of neural responses in the DMPFC and PCC for negative self-view versus case. Conclusion: These findings suggest that MBSR attenuates maladaptive habitual self-views by facilitating automatic (i.e., uninstructed) recruitment of cognitive and attention regulation neural networks. This highlights potentially important links between self-referential and cognitive-attention regulation systems and suggests that MBSR may enhance more adaptive social self-referential processes in patients with SAD.

Reduced dorsal anterior cingulate cortical activity during emotional regulation and top-down attentional control in generalized social phobia, generalized anxiety disorder, and comorbid generalized social phobia/generalized anxiety disorder

BACKGROUND

Generalized social phobia (GSP) and generalized anxiety disorder (GAD) are both associated with emotion dysregulation. Research implicates dorsal anterior cingulate cortex in both explicit emotion regulation (EER) and top-down attentional control (TAC). Although studies have examined these processes in GSP or GAD, no work compares findings across the two disorders or examines functioning in cases comorbid for both disorders (GSP/GAD). Here we compare the neural correlates of EER and TAC in GSP, GAD, and GSP/GAD.

METHODS

Medication-free adults with GSP (EER n = 19; TAC n = 18), GAD (EER n = 17; TAC n = 17), GSP/GAD (EER n = 17; TAC n = 15), and no psychopathology (EER n = 18; TAC n = 18) participated. During EER, individuals alternatively viewed and upregulated and downregulated responses to emotional pictures. During TAC, they performed an emotional Stroop task.

RESULTS

For both tasks, significant group × condition interactions emerged in dorsal anterior cingulate cortex and parietal cortices. Healthy adults showed significantly increased recruitment during emotion regulation, relative to emotion-picture viewing. GAD, GSP, and GSP/GAD subjects showed no such increases, with all groups differing from healthy adults but not from each other. Evidence of emotion-related disorder-specificity emerged in medial prefrontal cortex and amygdala. This disorder-specific responding varied as a function of emotion content but not emotion-regulatory demands.

CONCLUSIONS

GSP and GAD both involve reduced capacity for engaging emotion-regulation brain networks, whether explicitly or via TAC. A reduced ability to recruit regions implicated in top-down attention might represent a general risk factor for anxiety disorders.

Neuroscience of human social interactions and adult attachment style

Since its first description four decades ago, attachment theory (AT) has become one of the principal developmental psychological frameworks for describing the role of individual differences in the establishment and maintenance of social bonds between people. Yet, still little is known about the neurobiological underpinnings of attachment orientations and their well-established impact on a range of social and affective behaviors. In the present review, we summarize data from recent studies using cognitive and imaging approaches to characterize attachment styles and their effect on emotion and social cognition. We propose a functional neuroanatomical framework to integrate the key brain mechanisms involved in the perception and regulation of social emotional information, and their modulation by individual differences in terms of secure versus insecure (more specifically avoidant, anxious, or resolved versus unresolved) attachment traits. This framework describes how each individual's attachment style (built through interactions between personal relationship history and predispositions) may influence the encoding of approach versus aversion tendencies (safety versus threat) in social encounters, implicating the activation of a network of subcortical (amygdala, hippocampus, striatum) and cortical (insula, cingulate) limbic areas. These basic and automatic affective evaluation mechanisms are in turn modulated by more elaborate and voluntary cognitive control processes, subserving mental state attribution and emotion regulation capacities, implicating a distinct network in medial prefrontal cortex (mPFC), superior temporal sulcus (STS), and temporo-parietal junction (TPJ), among others. Recent neuroimaging data suggest that affective evaluation is decreased in avoidantly but increased in anxiously attached individuals. In turn, although data on cognitive control is still scarce, it points toward a possible enhancement of mental state representations associated with attachment insecurity and particularly anxiety. Emotion regulation strategies such as reappraisal or suppression of social emotions are also differentially modulated by attachment style. This research does not only help better understand the neural underpinnings of human social behavior, but also provides important insights on psychopathological conditions where attachment dysregulation is likely to play an important (causal) role.

A Cognitive Neuroscience Approach to Generalized Anxiety Disorder and Social Phobia

Generalized anxiety disorder (GAD) and social phobia (SP) are major anxiety disorders identified by the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV). They are comorbid, overlap in symptoms, yet present with distinct features (worry in GAD and fear of embarrassment in SP). Both have also been explained in terms of conditioning-based models. However, there is little reasoning currently to believe that GAD in adulthood reflects heightened conditionability or heightened threat processing—though patients with SP may show heightened processing of social threat stimuli. Moreover, the computational architectures that maintain these disorders in adulthood are different. For GAD this may reflect the development of an inefficient “worrying” strategy of emotional regulation. For SP this appears to reflect the atypical processing of self-referential information.

The pathology of social phobia is independent of developmental changes in face processing

OBJECTIVE

While social phobia in adolescence predicts the illness in adulthood, no study has directly compared the neural responses in social phobia in adults and adolescents. The authors examined neural responses to facial expressions in adults and adolescents with social phobia to determine whether the neural correlates of adult social phobia during face processing also manifest in adolescent social phobia.

METHOD

Blood-oxygen-level-dependent (BOLD) responses were compared in 39 medication-free participants with social phobia (25 adults and 14 adolescents) and 39 healthy comparison subjects (23 adults and 16 adolescents) matched on age, IQ, and gender. During fMRI scans, participants saw angry, fearful, and neutral expression stimuli while making a gender judgment.

RESULTS

Significant diagnosis-by-emotion interactions were observed within the amygdala and the rostral anterior cingulate cortex, as has previously been hypothesized. In these regions, both the adolescent and adult social phobia patients showed significantly increased BOLD responses relative to their respective age-matched comparison subjects, and there was no evidence of age-related modulation of between-group differences. These enhanced responses occurred specifically when viewing angry (rostral anterior cingulate cortex) and fearful (amygdala and rostral anterior cingulate cortex) expressions but not when viewing neutral expressions. In addition, the severity of social phobia was significantly correlated with the enhanced rostral anterior cingulate cortex response in the adults.

CONCLUSIONS

The neural correlates of adult social phobia during face processing also manifest in adolescents. Neural correlates that are observed in adult social phobia may represent the persistence of profiles established earlier in life rather than adaptive responses to such earlier perturbations or maturational changes. These cross-sectional observations might encourage longitudinal fMRI studies of adolescent social phobia.

Social norm processing in adult social phobia: atypically increased ventromedial frontal cortex responsiveness to unintentional (embarrassing) transgressions

OBJECTIVE

Little is known about the neural underpinnings of generalized social phobia, which is defined by a persistent heightened fear of social disapproval. Using event-related functional MRI (fMRI), the authors examined whether the intent of an event, which mediates the neural response to social disapproval in healthy individuals, differentially affects response in generalized social phobia.

METHOD

Sixteen patients with generalized social phobia and 16 healthy comparison subjects group-matched on age, gender, and IQ underwent fMRI scans while reading stories that involved neutral social events, unintentional social transgressions (e.g., choking on food at a party and coughing it up), or intentional social transgressions (e.g., disliking food at a party and spitting it out).

RESULTS

Significant group-by-transgression interactions were observed in ventral regions of the medial prefrontal cortex. Healthy individuals tended to show increased blood-oxygen-level-dependent responses to intentional relative to unintentional transgressions. Patients with generalized social phobia, however, showed significantly increased responses to the unintentional transgressions. They also rated the unintentional transgressions as significantly more embarrassing than did the comparison subjects. Results also revealed significant group main effects in the amygdala and insula bilaterally, reflecting elevated generalized social phobia responses in these regions to all event types.

CONCLUSIONS

These results further implicate the medial prefrontal cortex in the pathophysiology of generalized social phobia, specifically through its involvement in distorted self-referential processing. These results also further underscore the extended role of the amygdala and insula in the processing of social stimuli more generally in generalized social phobia.