Amygdala reactivity to emotional faces at high and low intensity in generalized social phobia: a 4-Tesla functional MRI study

Social anxiety prediction based on ERP features: A deep learning approach

BACKGROUND

Social Anxiety Disorder is traditionally diagnosed using subjective scales that may lack accuracy. Recently, EEG technology has gained importance for anxiety detection due to its ability to capture stable and objective neurophysiological activities. However, existing methods mainly focus on extracting EEG features during resting states, with limited use of psychologically features like Event-Related Potential (ERP) in task-related states for anxiety detection in deep learning frameworks.

METHODS

We collected EEG data from 63 participants exposed to four facial expressions and extracted task-relevant features. Using the EEGNet model, we predicted social anxiety and evaluated its performance using metrics such as accuracy, F1 score, sensitivity, and specificity. We compared EEGNet's performance with Deep Convolutional Neural Network (DeepConvNet), ShallowConvNet, Bi-directional Long Short-Term Memory (BiLSTM), and SVM. To assess the generalizability of the results, we carried out the same procedure on our prior dataset.

RESULTS

EEGNet outperformed other models, achieving 99.16 % accuracy with Late Positive Potential (LPP). ERP components yielded higher accuracy than time-domain and frequency-domain features for social anxiety recognition. Accuracy was better for neutral and negative facial stimuli. Consistency across two datasets indicates stability of findings.

LIMITATIONS

Due to limited publicly available task-state datasets, only our own were used. Future studies could assess generalizability on larger datasets from different sources.

CONCLUSIONS

We conducted the first test of ERP features in anxiety recognition tasks. Results show ERP features have greater potential in social anxiety recognition, with LPP exhibiting high stability and accuracy. Outcomes indicate recognizing social anxiety with negative or neutral facial stimuli is more useful.

Association between reward-related functional connectivity and tri-level mood and anxiety symptoms

Depression and anxiety are associated with abnormalities in brain regions that process rewards including the medial orbitofrontal cortex (mOFC), the ventral striatum (VS), and the amygdala. However, there are inconsistencies in these findings. This may be due to past reliance on categorical diagnoses that, while valuable, provide less precision than may be required to understand subtle neural changes associated with symptoms of depression and anxiety. In contrast, the tri-level model defines symptom dimensions that are common (General Distress) or relatively specific (Anhedonia-Apprehension, Fears) to depression and anxiety related disorders, which provide increased precision. In the current study, eligibility was assessed by quasi-orthogonal screening questionnaires measuring reward and threat sensitivity (Behavioral Activation Scale; Eysenck Personality Questionnaire-Neuroticism). These participants were assessed on tri-level symptom severity and completed the Monetary Incentive Delay task during fMRI scanning. VS-mOFC and VS-amygdala connectivity were estimated during reward anticipation and reward outcome. Heightened General Distress was associated with lower VS-mOFC connectivity during reward anticipation (b = -0.064, p = 0.021) and reward outcome (b = -0.102, p = 0.014). Heightened Anhedonia-Apprehension was associated with greater VS-amygdala connectivity during reward anticipation (b = 0.065, p = 0.004). The present work has important implications for understanding the coupling between the mOFC and vS and the amygdala and the vS during reward processing in the pathophysiology of mood and anxiety symptoms and for developing targeted behavioral, pharmacological, and neuromodulatory interventions to help manage these symptoms.

Candidate Biological Markers for Social Anxiety Disorder: A Systematic Review

Social anxiety disorder (SAD) is a common psychiatric condition associated with a high risk of psychiatric comorbidity and impaired social/occupational functioning when not promptly treated. The identification of biological markers may facilitate the diagnostic process, leading to an early and proper treatment. Our aim was to systematically review the available literature about potential biomarkers for SAD. A search in the main online repositories (PubMed, ISI Web of Knowledge, PsychInfo, etc.) was performed. Of the 662 records screened, 61 were included. Results concerning cortisol, neuropeptides and inflammatory/immunological/neurotrophic markers remain inconsistent. Preliminary evidence emerged about the role of chromosome 16 and the endomannosidase gene, as well as of epigenetic factors, in increasing vulnerability to SAD. Neuroimaging findings revealed an altered connectivity of different cerebral areas in SAD patients and amygdala activation under social threat. Some parameters such as salivary alpha amylase levels, changes in antioxidant defenses, increased gaze avoidance and QT dispersion seem to be associated with SAD and may represent promising biomarkers of this condition. However, the preliminary positive correlations have been poorly replicated. Further studies on larger samples and investigating the same biomarkers are needed to identify more specific biological markers for SAD.

Sosyal Biliş Becerilerinin Sosyal Kaygı Üzerindeki Yordayıcı Etkisi

Bu çalışmanın temel amacı sosyal kaygı ile sosyal biliş becerileri (duygu tanıma/ayırt etme, zihin kuramı, atıf yanlılığı, sosyal işlevsellik) arasındaki ilişkiyi incelemek ve sosyal biliş becerilerinin sosyal kaygıyı yordama gücünü araştırmaktır. Çalışmada ayrıca sosyal kaygı, sosyal biliş becerileri ve depresyon puanlarının cinsiyet, yaş, bildirilen tanı durumu ve sosyal kaygı düzeyine göre farklılaşıp farklılaşmadığı araştırılmıştır. Çalışmanın örneklemini, 18-60 yaşları arasında bulunan toplam 385 kişi oluşturmuştur. Araştırma verileri çevrimiçi olarak Liebowitz Sosyal Anksiyete Ölçeği, Yüzde Dışavuran Duyguların Tanınması ve Ayırt Edilmesi Testi, Gözlerden Zihin Okuma Testi, İçsel, Kişisel ve Durumsal Atıflar Ölçeği, Sosyal İşlevsellik Ölçeği, Beck Depresyon Envanteri ve Sosyodemografik Bilgi Formu kullanılarak katılımcılardan toplanmıştır. Sosyal kaygı ile duygu tanıma, duygu ayırt etme ve gözlerden zihin okuma arasında negatif, dışsallaştırma yanlılığı ve depresyon ile ise pozitif yönde anlamlı ilişki olduğu belirlenmiştir. Depresyon, duygu tanıma ve ayırt etme, gözlerden zihin okuma ve öncül sosyal etkinlikler ölçek puanlarının sosyal kaygıyı anlamlı düzeyde yordadığı bulunmuştur. Bu değişkenler sosyal kaygıya ilişkin toplam varyansın %52’sini açıklamaktadır. Ayrıca, depresyon etkisi kontrol edildiğinde sosyal biliş becerilerinin sosyal kaygıya ilişkin varyansın %32’sini açıkladığı görülmüştür. Sosyal biliş becerilerindeki bozulmanın ve depresyon puanlarının sosyal kaygının artışıyla ilişkili olduğu belirlenmiştir. Araştırmadan elde edilen sonuçlara göre, sosyal kaygıyı önlemeye yönelik önerilerde bulunulmuştur. Müdahale programları içerisinde bireylerin kişilerarası iletişimi için önemli olan sosyal biliş becerilerini geliştirmeye yönelik etkinliklere yer verilmesinin yararlı olacağı önerilmektedir.

The brain activation of anxiety disorders with emotional stimuli-an fMRI ALE meta-analysis

Numerous studies have analyzed the state of brain activation about anxiety disorders under emotional stimuli. However, there is no meta-analysis to assess the commonality and specificity activation concerning different subtypes of anxiety. Here, we used ALE to assess this. 29 studies revealed increased bilateral amygdala, anterior cingulate gyrus, parahippocampal gyrus activation in anxiety disorders during emotional stimuli. Moreover, we observed decreased activations in the posterior cingulate, lingual gyrus, and precuneus. In sub-analysis, although different anxiety showed dissimilar activations, the principal activations were observed in limbic lobe, which might indicate the limbic circuit was the main neural reflection of anxiety symptoms.

Social anxiety and behavioral assessments of social cognition: A systematic review

BACKGROUND

Social anxiety is highly prevalent and has increased in young adults during the COVID-19 pandemic. Since social anxiety negatively impacts interpersonal functioning, identifying aspects of social cognition that may be impaired can increase our understanding of the development and maintenance of social anxiety disorder. However, to date, studies examining associations between social anxiety and social cognition have resulted in mixed findings.

METHODS

The aim of this systematic review was to summarize the literature on the association between social anxiety and social cognition, while also considering several potential moderators and covariates that may influence findings.

RESULTS

A systematic search identified 52 studies. Results showed mixed evidence for the association between social anxiety and lower-level social cognitive processes (emotion recognition and affect sharing) and a trend for a negative association with higher-level social cognitive processes (theory of mind and empathic accuracy). Most studies examining valence-specific effects found a significant negative association for positive and neutral stimuli.

LIMITATIONS

Not all aspects of social cognition were included (e.g., attributional bias) and we focused on adults and not children, limiting the scope of the review.

CONCLUSIONS

Future studies would benefit from the inclusion of relevant moderators and covariates, multiple well-validated measures within the same domain of social cognition, and assessments of interpersonal functioning outside of the laboratory. Additional research examining the moderating role of attention or interpretation biases on social cognitive performance, and the potential benefit of social cognitive skills training for social anxiety, could inform and improve existing cognitive behavioral interventions.

The Relation Between College Students' Social Anxiety and Mobile Phone Addiction: The Mediating Role of Regulatory Emotional Self-Efficacy and Subjective Well-Being

The present study explores the underlying mechanism of the relationship between college students' social anxiety and mobile phone addiction. Adopting college students' social anxiety scale, regulatory emotional self-efficacy scale, subjective well-being scale and mobile phone addiction scale, this research tested valid samples of 680 Chinese college students. The results indicated that social anxiety exerted a significant and positive impact on mobile phone addiction. Regulatory emotional self-efficacy played a partial mediating role between social anxiety and mobile phone addiction. Subjective well-being also played a partial mediating role between social anxiety and mobile phone addiction. Moreover, both regulatory emotional self-efficacy and subjective well-being were found to play a chain mediating role between social anxiety and mobile phone addiction. The study provides valuable insights into the impact of college students' social anxiety on mobile phone addiction.

Neural correlates of attentional control in social anxiety disorder: the impact of early-life adversity and DNA methylation

BACKGROUND

Social anxiety disorder is characterized by intense fear and avoidance of social interactions and scrutiny by others. Although alterations in attentional control seem to play a central role in the psychopathology of social anxiety disorder, the neural underpinnings in prefrontal brain regions have not yet been fully clarified.

METHODS

The present study used functional MRI in participants (age 18-50 yr) with social anxiety disorder (n = 42, 31 female) and without (n = 58, 33 female). It investigated the interrelation of the effects of social anxiety disorder and early-life adversity (a main environmental risk factor of social anxiety disorder) on brain activity during an attentional control task. We applied DNA methylation analysis to determine whether epigenetic modulation in the gene encoding the glucocorticoid receptor, NR3C1, might play a mediating role in this process.

RESULTS

We identified 2 brain regions in the left and medial prefrontal cortex that exhibited an interaction effect of social anxiety disorder and early-life adversity. In participants with low levels of early-life adversity, neural activity in response to disorder-related stimuli was increased in association with social anxiety disorder. In participants with high levels of early-life adversity, neural activity was increased only in participants without social anxiety disorder. NR3C1 DNA methylation partly mediated the effect of social anxiety disorder on brain activity as a function of early-life adversity.

LIMITATIONS

The absence of behavioural correlates associated with social anxiety disorder limited functional interpretation of the results.

CONCLUSION

These findings demonstrate that the neurobiological processes that underlie social anxiety disorder might be fundamentally different depending on experiences of early-life adversity. Long-lasting effects of early-life adversity might be encoded in NR3C1 DNA methylation and entail alterations in social anxiety disorder-related activity patterns in the neural network of attentional control.

The endocannabinoid system in social anxiety disorder: from pathophysiology to novel therapeutics

Social anxiety disorder (SAD) is a highly prevalent psychiatric disorder that presents with an early age of onset, chronic disease course, and increased risk of psychiatric comorbidity. Current treatment options for SAD are associated with low response rates, suboptimal efficacy, and possible risk of adverse effects. Investigation of new neurobiological mechanisms may aid in the identification of more specific therapeutic targets for the treatment of this disorder. Emerging evidence suggests that the endogenous cannabinoid system, also referred to as the endocannabinoid system (ECS), could play a potential role in the pathophysiology of SAD. This review discusses the known pathophysiological mechanisms of SAD, the potential role of the ECS in this disorder, current drugs targeting the ECS, and the potential of these novel compounds to enhance the therapeutic armamentarium for SAD. Further investigational efforts, specifically in human populations, are warranted to improve our knowledge of the ECS in SAD.

The altered early components and the decisive later process underlying attention bias modification in social anxiety: evidence from event-related potentials

Attention bias modification (ABM) is a potential intervention in relieving social anxiety symptoms, while its underlying neural mechanisms are not yet understood. The current study included 63 college students with social anxiety. Participants were assigned to the attention modification program (AMP, n = 20), the attention control condition (ACC, n = 20) and the passive waiting group (PW, n = 23). Questionnaires and the emotional Stroop task with EEG recordings were used to assess whether and how the 4-week ABM period affected emotional symptoms and specific emotional processing. Results showed that the two training groups (AMP and ACC) produced comparable emotional improvements and both showed a decrease in negative bias compared with the PW group. The ERP results indicated that despite no significant ERP changes in the PW group, the ACC group exhibited a greater N1, whereas the AMP group exhibited a reduced VPP at the post-test stage compared to the pre-test stage. Besides, both training groups showed a similar late positive potential (LPP) reduction. Notably, the reduction in LPP was positively correlated with behavioral and symptom improvement. Thus, manipulations unique to ABM (face-target contingency) primarily modulate the early attention distribution of material-related stimuli. However, the clinical benefits of attention training may be due to later cognitive-affective mechanisms.

Amygdala volume and social anxiety symptom severity: Does segmentation technique matter?

The amygdala factors prominently in neurobiological models of social anxiety (SA), yet amygdala volume findings regarding SA have been inconsistent and largely focused on case-control characterization. One source of discrepant findings could be variability in volumetric techniques. Therefore, we compared amygdala volumes derived via an automated technique (Freesurfer) against a manually corrected approach, also involving Freesurfer. Additionally, we tested whether the relationship between volume and SA symptom severity would differ across volumetric techniques. We pooled participants (n = 76) from archival studies. SA severity was assessed with the Liebowitz Social Anxiety Scale; scores ranged from non-clinical to clinical levels. Freesurfer produced significantly larger amygdalar volumes for participants with poor image quality. Even after excluding such participants, paired sample t-tests showed Freesurfer's boundaries produced significantly larger amygdalar volumes than manually corrected ones, bilaterally. Yet, intra-class correlation coefficients between the two methods were high, which suggests that Freesurfer's over-estimation of amygdala volume was systemic. Regardless of segmentation technique, volumes were not associated with SA symptom severity. Potentially, amygdala sub-regions may yield clearer patterns regarding SA symptoms. Further, our study underscores the importance of image quality for segmentation of the amygdala, and image quality may be particularly valuable when examining anatomical data for subtle inter-individual differences.

Soothing the emotional brain: modulation of neural activity to personal emotional stimulation by social touch

Social touch may modulate emotions, but the neurobehavioral correlates are poorly understood. Here, we investigated neural responses to a picture of a deceased close person and if neural activity and connectivity are modulated by social touch from one's romantic partner. Using functional magnetic resonance imaging, we found altered reactivity in several brain areas including the anterior cingulate cortex (ACC) and the anterior insula in response to the personal picture compared to a picture of an unfamiliar person. Hand holding with the romantic partner, compared to being alone, reduced reactivity in the ACC and cerebellum and provided subjective comfort. To separate physical touch from the emotional effect of partner presence, we evaluated hand holding with the partner relative to a stranger and found reduced reactivity in the anterior insula. Connectivity between the anterior insula and the ACC was reduced during partner touch, and the connectivity strength was negatively related to attachment security, with higher reported partner security associated with weaker connectivity. Overall, holding hands with one's partner attenuates reactivity in emotional brain areas and reduces between-region connectivity.

Amygdala reactivity and connectivity during social and non-social aversive stimulation in social anxiety disorder

Social anxiety disorder (SAD) is characterized by exaggerated amygdala reactivity in response to symptom provocation, but it is unclear if such hyper-reactivity is elicited by disorder-specific challenges only or characterizes reactions to aversive stimuli in general. Here, using functional magnetic resonance imaging in 14 patients with SAD, as compared to 12 healthy controls, we found that amygdala hyper-reactivity is confined to disorder-relevant social stimulation. SAD patients displayed increased amygdala reactivity to fearful as compared to neutral facial pictures, but not in response to generally aversive but mainly non-social stimulation when compared to neutral pictorial stimuli taken from the International Affective Picture System. The increased amygdala reactivity was not mediated by an altered prefrontal inhibition among SAD patients as compared to controls, suggesting increased bottom-up processes rather than attenuated top-down control. In conclusion, the enhanced amygdala reactivity in SAD seems specific to socially relevant stimuli rather than aversive stimuli in general.

Neural response patterns in spider, blood-injection-injury and social fearful individuals: new insights from a simultaneous EEG/ECG-fMRI study

In the present simultaneous EEG/ECG-fMRI study we compared the temporal and spatial characteristics of the brain responses and the cardiac activity during fear picture processing between spider, blood-injection-injury (BII) and social fearful as well as healthy (non-fearful) volunteers. All participants were presented with two neutral and six fear-related blocks of pictures: two social, two spider and two blood/injection fear blocks. In a social fear block neutral images were occasionally interspersed with photographs of angry faces and social exposure scenes. In spider and blood/injection fear blocks neutral pictures were interspersed with spider fear-relevant and blood/injection pictures, respectively. When compared to healthy controls the social fear group responded with increased activations in the anterior orbital, middle/anterior cingulate and middle/superior temporal areas for pictures depicting angry faces and with a few elevated superior frontal activations for social exposure scenes. In the blood/injection fear group, heart rate was decreased and the activity in the middle/inferior frontal and visual processing regions was increased for blood/injection pictures. The HR decrease for blood/injection pictures correlated with increased frontal responses. In the spider fear group, spider fear-relevant pictures triggered increased activations within a broad subcortical and cortical neural fear network. The HR response for spider fear-relevant stimuli was increased and correlated with an increased insula and hippocampus activity. When compared to healthy controls, all fear groups showed higher LPP amplitudes for their feared cues and an overall greater P1 hypervigilance effect. Contrasts against the fear control groups showed that the increased responses for fear-specific stimuli are mostly related to specific fears and not to general anxiety proneness. The results suggest different engagement of cognitive evaluation and down-regulation strategies and an overall increased sensitization of the fear system in the three fear groups.

Brain activation in response to overt and covert fear and happy faces in women with borderline personality disorder

Borderline personality disorder (BPD) is a serious condition involving emotion dysregulation. Past research has identified BPD-associated differences within fronto-limbic circuitry during conditions of processing negative emotion. Functional magnetic resonance imaging (fMRI) paradigms that incorporate overt and covert (masked) presentations of emotional stimuli can provide complementary information about neural systems underlying emotion processing (e.g., both slow [overt] and fast [covert; automatic] processing pathways). This study examined brain activation during processing of overt and covert presentations of emotional faces in 12 women with BPD and 12 age-matched healthy controls. To assess a range of emotional valence and arousal, we examined responses to fear, happy and neutral expressions. All participants underwent an fMRI scanning session in which participants passively viewed emotional faces. Scanning sessions consisted of 5 runs including: (1) Overt Fear (OF) versus Neutral (N), (2) Covert Fear (CF) versus Covert Neutral (CN), (3) Overt Happy (OH) versus N, (4) Covert Happy (CH) versus CN, and (5) N versus fixation. We compared whole-brain activation between groups for each run. In response to overt fear, BPD patients showed greater activation both in left amygdala and in several frontal cortical regions. There were no significant differences in brain activation in response to overt happy faces. In response to covert fear and covert happy stimuli, the BPD group also showed greater activation than controls in several regions including frontal and temporal cortical regions, as well as cerebellum and thalamus. These findings add to prior reports suggesting increased amygdala activation in BPD, but we found this only in the overt fear versus fixation condition. In this sample, BPD patients showed hyper-activation, rather than hypo-activation, of cortical regulatory regions during overt fear. Enhanced cortical recruitment in response to covert fear and happy faces in BPD could reflect a more extended response system in which stimuli that typically only activate automatic pathways are additionally tapping into cortical regulatory systems. The observation of this pattern both in response to fear and in response to happy presentations suggests that the effect of arousal may be as or more impactful than the effect of emotional valence.

How does gaze direction affect facial processing in social anxiety? -An ERP study

Previous behavioral studies have demonstrated an effect of eye gaze direction on the processing of emotional expressions in adults with social anxiety. However, specific brain responses to the interaction between gaze direction and facial expressions in social anxiety remain unclear. The present study aimed to explore the time course of such interaction using event-related potentials (ERPs) in participants with social anxiety. High socially anxious individuals and low socially anxious individuals were asked to identify the gender of angry or neutral faces with direct or averted gaze while their behavioral performance and electrophysiological data were monitored. We found that identification of angry faces with direct but not averted gaze elicited larger N2 amplitude in high socially anxious individuals compared to low socially anxious individuals, while identification of neutral faces did not produce any gaze modulation effect. Moreover, the N2 was correlated with increased anxiety severity upon exposure to angry faces with direct gaze. Therefore, our results suggest that gaze direction modulates the processing of threatening faces in social anxiety. The N2 component elicited by angry faces with direct gaze could be a state-dependent biomarker of social anxiety and may be an important reference biomarker for social anxiety diagnosis and intervention.

Functional and neurochemical interactions within the amygdala-medial prefrontal cortex circuit and their relevance to emotional processing

The amygdala-medial prefrontal cortex (mPFC) circuit plays a key role in emotional processing. GABA-ergic inhibition within the mPFC has been suggested to play a role in the shaping of amygdala activity. However, the functional and neurochemical interactions within the amygdala-mPFC circuits and their relevance to emotional processing remain unclear. To investigate this circuit, we obtained resting-state functional magnetic resonance imaging (rs-fMRI) and proton MR spectroscopy in 21 healthy subjects to assess the potential relationship between GABA levels within mPFC and the amygdala-mPFC functional connectivity. Trait anxiety was assessed using the State-Trait Anxiety Inventory (STAI-Y2). Partial correlations were used to measure the relationships among the functional connectivity outcomes, mPFC GABA levels and STAI-Y2 scores. Age, educational level and amount of the gray and white matters within 1H-MRS volume of interest were included as nuisance variables. The rs-fMRI signals of the amygdala and the vmPFC were significantly anti-correlated. This negative functional coupling between the two regions was inversely correlated with the GABA+/tCr level within the mPFC and the STAI-Y2 scores. We suggest a close relationship between mPFC GABA levels and functional interactions within the amygdala-vmPFC circuit, providing new insights in the physiology of emotion.

Neural responses to social threat and predictors of cognitive behavioral therapy and acceptance and commitment therapy in social anxiety disorder

Previous research has often highlighted hyperactivity in emotion regions to simple, static social threat cues in social anxiety disorder (SAD). Investigation of the neurobiology of SAD using more naturalistic paradigms can further reveal underlying mechanisms and how these relate to clinical outcomes. We used fMRI to investigate responses to novel dynamic rejection stimuli in individuals with SAD (N=70) and healthy controls (HC; N=17), and whether these responses predicted treatment outcomes following cognitive behavioral therapy (CBT) or acceptance and commitment therapy (ACT). Both HC and SAD groups reported greater distress to rejection compared to neutral social stimuli. At the neural level, HCs exhibited greater activations in social pain/rejection regions, including dorsal anterior cingulate cortex and anterior insula, to rejection stimuli. The SAD group evidenced a different pattern, with no differences in these rejection regions and relatively greater activations in the amygdala and other regions to neutral stimuli. Greater responses in anterior cingulate cortex and the amygdala to rejection vs. neutral stimuli predicted better CBT outcomes. In contrast, enhanced activity in sensory-focused posterior insula predicted ACT responses.

Attentional mechanisms of social perception are biased in social phobia

Previous studies of social phobia have reported an increased vigilance to social threat cues but also an avoidance of socially relevant stimuli such as eye gaze. The primary aim of this study was to examine attentional mechanisms relevant for perceiving social cues by means of abnormalities in scanning of facial features in patients with social phobia. In two novel experimental paradigms, patients with social phobia and healthy controls matched on age, gender and education were compared regarding their gazing behavior towards facial cues. The first experiment was an emotion classification paradigm which allowed for differentiating reflexive attentional shifts from sustained attention towards diagnostically relevant facial features. In the second experiment, attentional orienting by gaze direction was assessed in a gaze-cueing paradigm in which non-predictive gaze cues shifted attention towards or away from subsequently presented targets. We found that patients as compared to controls reflexively oriented their attention more frequently towards the eyes of emotional faces in the emotion classification paradigm. This initial hypervigilance for the eye region was observed at very early attentional stages when faces were presented for 150ms, and persisted when facial stimuli were shown for 3s. Moreover, a delayed attentional orienting into the direction of eye gaze was observed in individuals with social phobia suggesting a differential time course of eye gaze processing in patients and controls. Our findings suggest that basic mechanisms of early attentional exploration of social cues are biased in social phobia and might contribute to the development and maintenance of the disorder.

Amygdalar volumetric correlates of social anxiety in offspring of parents with bipolar disorder

The prevalence of social anxiety disorder is high in offspring of parents with bipolar disorder (BD) and anxiety may be a significant risk factor in these youth for developing BD. We compared social anxiety symptoms between BD offspring with mood symptoms (high-risk group for developing BD I or II: HR) and healthy controls (HC). We also explored the correlations between the amygdalar volumes and social anxiety symptoms in the HR group with high social anxiety scores (HRHSA) due to the potential involvement of the amygdala in the pathophysiology of both BD and social anxiety. Youth participating in the study included 29h and 17HC of comparable age and gender. To assess social anxiety symptoms, we used the Multidimensional Anxiety Scale for Children (MASC) social anxiety subscale. The HR group's MASC social anxiety score was significantly higher than that of the HC group. Among the 29h, 17 subjects (58.6%) showed high social anxiety and they were classified as the HRHSA group. No significant difference was observed in amygdalar volume between the HRHSA and HC groups. However, there were significant negative correlations between amydalar volumes and MASC social anxiety score in the HRHSA group. These findings have implications for the link between amygdalar structure and both anxiety and mood control. This link may serve to implicate high social anxiety as a risk marker for future BD development.

The Effect of Affective Context on Visuocortical Processing of Neutral Faces in Social Anxiety

It has been demonstrated that verbal context information alters the neural processing of ambiguous faces such as faces with no apparent facial expression. In social anxiety, neutral faces may be implicitly threatening for socially anxious individuals due to their ambiguous nature, but even more so if these neutral faces are put in self-referential negative contexts. Therefore, we measured event-related brain potentials (ERPs) in response to neutral faces which were preceded by affective verbal information (negative, neutral, positive). Participants with low social anxiety (LSA; n = 23) and high social anxiety (HSA; n = 21) were asked to watch and rate valence and arousal of the respective faces while continuous EEG was recorded. ERP analysis revealed that HSA showed elevated P100 amplitudes in response to faces, but reduced structural encoding of faces as indexed by reduced N170 amplitudes. In general, affective context led to an enhanced early posterior negativity (EPN) for negative compared to neutral facial expressions. Moreover, HSA compared to LSA showed enhanced late positive potentials (LPP) to negatively contextualized faces, whereas in LSA this effect was found for faces in positive contexts. Also, HSA rated faces in negative contexts as more negative compared to LSA. These results point at enhanced vigilance for neutral faces regardless of context in HSA, while structural encoding seems to be diminished (avoidance). Interestingly, later components of sustained processing (LPP) indicate that LSA show enhanced visuocortical processing for faces in positive contexts (happy bias), whereas this seems to be the case for negatively contextualized faces in HSA (threat bias). Finally, our results add further new evidence that top-down information in interaction with individual anxiety levels can influence early-stage aspects of visual perception.

Beyond emotions: A meta-analysis of neural response within face processing system in social anxiety

Patients with social anxiety disorder (SAD) experience anxiety and avoidance in face-to-face interactions. We performed a meta-analysis of functional magnetic resonance imaging (fMRI) studies in SAD to provide a comprehensive understanding of the neural underpinnings of face perception in this disorder. To this purpose, we adopted an innovative approach, asking authors for unpublished data. This is a common procedure for behavioral meta-analyses, which, however has never been used in neuroimaging studies. We searched Pubmed with the key words "Social Anxiety AND faces" and "Social Phobia AND faces." Then, we selected those fMRI studies for which we were able to obtain data for the comparison between SAD and healthy controls (HC) in a face perception task, either from the published papers or from the authors themselves. In this way, we obtained 23 studies (totaling 449 SAD and 424 HC individuals). We identified significant clusters in which faces evoked a higher response in SAD in bilateral amygdala, globus pallidus, superior temporal sulcus, visual cortex, and prefrontal cortex. We also found a higher activity for HC in the lingual gyrus and in the posterior cingulate. Our findings show that altered neural response to face in SAD is not limited to emotional structures but involves a complex network. These results may have implications for the understanding of SAD pathophysiology, as they suggest that a dysfunctional face perception process may bias patient person-to-person interactions.

Neural correlates of emotional interference in social anxiety disorder

Disorder-relevant but task-unrelated stimuli impair cognitive performance in social anxiety disorder (SAD); however, time course and neural correlates of emotional interference are unknown. The present study investigated time course and neural basis of emotional interference in SAD using event-related functional magnetic resonance imaging (fMRI). Patients with SAD and healthy controls performed an emotional stroop task which allowed examining interference effects on the current and the succeeding trial. Reaction time data showed an emotional interference effect in the current trial, but not the succeeding trial, specifically in SAD. FMRI data showed greater activation in the left amygdala, bilateral insula, medial prefrontal cortex (mPFC), dorsal anterior cingulate cortex (ACC), and left opercular part of the inferior frontal gyrus during emotional interference of the current trial in SAD patients. Furthermore, we found a positive correlation between patients' interference scores and activation in the mPFC, dorsal ACC and left angular/supramarginal gyrus. Taken together, results indicate a network of brain regions comprising amygdala, insula, mPFC, ACC, and areas strongly involved in language processing during the processing of task-unrelated threat in SAD. However, specifically the activation in mPFC, dorsal ACC, and left angular/supramarginal gyrus is associated with the strength of the interference effect, suggesting a cognitive network model of attentional bias in SAD. This probably comprises exceeded allocation of attentional resources to disorder-related information of the presented stimuli and increased self-referential and semantic processing of threat words in SAD.

Neural correlates of self-focused attention in social anxiety

Socially anxious individuals tend to shift their attention away from external socially threatening cues and instead become highly self-focused. Such heightened self-focused attention has been suggested to be involved in the development and maintenance of social anxiety disorder. This study used functional magnetic resonance imaging to investigate the neural correlates of self-focused attention in 16 high socially anxious (HSA) and 16 low socially anxious (LSA) individuals. Participants were instructed to focus their attention either inwardly or outwardly during a simulated social situation. Results indicate hyperactivation of medial prefrontal cortex (mPFC), temporo-parietal junction (TPJ) and temporal pole during inward vs outward attention in HSA compared with LSA participants. Furthermore, activation of mPFC, right anterior insula, TPJ and posterior cingulate cortex was positively correlated with the trait of self-focused attention in HSA subjects. Results highlight the prominent role of the mPFC and other cortical structures in abnormal self-focused attention in social anxiety. Finally, findings for the insula suggest increased processing of bodily states that is related to the amount of habitual self-focused attention in social anxiety.

Neurobiological correlates of social anxiety disorder: an update

Social anxiety disorder (SAD) is a condition characterized by pervasiveness and impairment in social functioning, with a prevalence in the general population between 1.9% and 12.1%. The most consistent findings on its neurobiological underpinnings involve a wide range of neurotransmitters (serotonin, norepinephrine, glutamate, and GABA) and neuropeptides (oxytocin), but no comprehensive hypothesis is yet available. In particular, oxytocin is becoming increasingly established as a "prosocial neuropeptide" and, as such, is a major focus of current research, with a great range of therapeutic applications including SAD treatment. Specifically, the amygdala plays a pivotal role in conditioning and processing of fear, and exaggerated amygdala responses in SAD patients have been observed during various social-emotional stimuli. In addition to the amygdala, other brain areas of interest in SAD-related circuitry are represented by the medial prefrontal cortex, dorsal raphe, striatum, locus coeruleus, prefrontal cortex, insular cortex, and anterior cingulate cortex. The aim of this review is to provide an update on neurobiological correlates of SAD, with a special focus on neurotransmitters and brain areas possibly involved, and suggestions for future research that could lead to more specific therapeutic interventions.

Effects of oxytocin on attention to emotional faces in healthy volunteers and highly socially anxious males

BACKGROUND

Evidence suggests that individuals with social anxiety demonstrate vigilance to social threat, whilst the peptide hormone oxytocin is widely accepted as supporting affiliative behaviour in humans.

METHODS

This study investigated whether oxytocin can affect attentional bias in social anxiety. In a double-blind, randomized, placebo-controlled, within-group study design, 26 healthy and 16 highly socially anxious (HSA) male volunteers (within the HSA group, 10 were diagnosed with generalized social anxiety disorder) were administered 24 IU of oxytocin or placebo to investigate attentional processing in social anxiety. Attentional bias was assessed using the dot-probe paradigm with angry, fearful, happy and neutral face stimuli.

RESULTS

In the baseline placebo condition, the HSA group showed greater attentional bias for emotional faces than healthy individuals. Oxytocin reduced the difference between HSA and non-socially anxious individuals in attentional bias for emotional faces. Moreover, it appeared to normalize attentional bias in HSA individuals to levels seen in the healthy population in the baseline condition. The biological mechanisms by which oxytocin may be exerting these effects are discussed.

CONCLUSIONS

These results, coupled with previous research, could indicate a potential therapeutic use of this hormone in treatment for social anxiety.

Of 'disgrace' and 'pain'--corticolimbic interaction patterns for disorder-relevant and emotional words in social phobia

Limbic hyperactivation and an impaired functional interplay between the amygdala and the prefrontal cortex are discussed to go along with, or even cause, pathological anxiety. Within the multi-faceted group of anxiety disorders, the highly prevalent social phobia (SP) is characterized by excessive fear of being negatively evaluated. Although there is widespread evidence for amygdala hypersensitivity to emotional faces in SP, verbal material has rarely been used in imaging studies, in particular with an eye on disorder-specificity. Using functional magnetic resonance imaging (fMRI) and a block design consisting of (1) overall negative, (2) social-phobia related, (3) positive, and (4) neutral words, we studied 25 female patients with social phobia and 25 healthy female control subjects (HC). Results demonstrated amygdala hyperactivation to disorder-relevant but not to generally negative words in SP patients, with a positive correlation to symptom severity. A functional connectivity analysis revealed a weaker coupling between the amygdala and the left middle frontal gyrus in patients. Symptom severity was negatively related to connectivity strength between the amygdala and the ventromedial prefrontal and orbitofrontal cortex (Brodmann Area 10 and 11). The findings clearly support the view of a hypersensitive threat-detection system, combined with disorder-related alterations in amygdala-prefrontal cortex connectivity in pathological anxiety.

A meta-analysis and scoping review of social cognition performance in social phobia, posttraumatic stress disorder and other anxiety disorders

Social cognition deficits are observed in a variety of psychiatric illnesses. However, data concerning anxiety disorders are sparse and difficult to interpret. This meta-analysis aims at determining if social cognition is affected in social phobia (SP) or posttraumatic stress disorder (PTSD) compared to non-clinical controls and the specificity of such deficits relatively to other anxiety disorders. The scoping review aims to identify research gaps in the field. Forty studies assessing mentalizing, emotion recognition, social perception/knowledge or attributional style in anxiety disorders were included, totalizing 1417 anxious patients and 1321 non-clinical controls. Results indicate distinct patterns of social cognition impairments: people with PTSD show deficits in mentalizing (effect size d = -1.13) and emotion recognition (d = -1.6) while other anxiety disorders including SP showed attributional biases (d = -0.53 to d = -1.15). The scoping review identified several under investigated domains of social cognition in anxiety disorders. Some recommendations are expressed for future studies to explore the full range of social cognition in anxiety disorders and allow direct comparisons between different disorders.

Lesion side matters - an fMRI study on the association between neural correlates of watching dynamic fearful faces and their evaluation in patients with temporal lobe epilepsy

Most studies assessing facial affect recognition in patients with TLE reported emotional disturbances in patients with TLE. Results from the few fMRI studies assessing neural correlates of affective face processing in patients with TLE are divergent. Some, but not all, found asymmetrical mesiotemporal activations, i.e., stronger activations within the hemisphere contralateral to seizure onset. Little is known about the association between neural correlates of affect processing and subjective evaluation of the stimuli presented. Therefore, we investigated the neural correlates of processing dynamic fearful faces in 37 patients with mesial temporal lobe epilepsy (TLE; 18 with left-sided TLE (lTLE), 19 with right-sided TLE (rTLE)) and 20 healthy subjects. We additionally assessed individual ratings of the fear intensity and arousal perception of the fMRI stimuli and correlated these data with the activations induced by the fearful face paradigm and activation lateralization within the mesiotemporal structures (in terms of individual lateralization indices, LIs). In healthy subjects, whole-brain analysis showed bilateral activations within a widespread network of mesial and lateral temporal, occipital, and frontal areas. The patient groups activated different parts of this network. In patients with lTLE, we found predominantly right-sided activations within the mesial and lateral temporal cortices and the superior frontal gyrus. In patients with rTLE, we observed bilateral activations in the posterior regions of the lateral temporal lobe and within the occipital cortex. Mesiotemporal region-of-interest analysis showed bilateral symmetric activations associated with watching fearful faces in healthy subjects. According to the region of interest and LI analyses, in the patients with lTLE, mesiotemporal activations were lateralized to the right hemisphere. In the patients with rTLE, we found left-sided mesiotemporal activations. In patients with lTLE, fear ratings were comparable to those of healthy subjects and were correlated with relatively stronger activations in the right compared to the left amygdala. Patients with rTLE showed significantly reduced fear ratings compared to healthy subjects, and we did not find associations with amygdala lateralization. Although we found stronger activations within the contralateral mesial temporal lobe in the majority of all patients, our results suggest that only in the event of left-sided mesiotemporal damage is the right mesial temporal lobe able to preserve intact facial fear recognition. In the event of right-sided mesiotemporal damage, fear recognition is disturbed. This underlines the hypothesis that the right amygdala is biologically predisposed to processing fear, and its function cannot be fully compensated in the event of right-sided mesiotemporal damage.

Area-dependent time courses of brain activation during video-induced symptom provocation in social anxiety disorder

BACKGROUND

Previous functional imaging studies using symptom provocation in patients with social anxiety disorder (SAD) reported inconsistent findings, which might be at least partially related to different time-dependent activation profiles in different brain areas. In the present functional magnetic resonance imaging study, we used a novel video-based symptom provocation design in order to investigate the magnitude and time course of activation in different brain areas in 20 SAD patients and 20 healthy controls.

RESULTS

The disorder-related videos induced increased anxiety in patients with SAD as compared to healthy controls. Analyses of brain activation to disorder-related versus neutral video clips revealed amygdala activation during the first but not during the second half of the clips in patients as compared to controls. In contrast, the activation in the insula showed a reversed pattern with increased activation during the second but not during the first half of the video clips. Furthermore, a cluster in the anterior dorsal anterior cingulate cortex showed a sustained response for the entire duration of the videos.

CONCLUSIONS

The present findings suggest that different regions of the fear network show differential temporal response patterns during video-induced symptom provocation in SAD. While the amygdala is involved during initial threat processing, the insula seems to be more involved during subsequent anxiety responses. In accordance with cognitive models of SAD, a medial prefrontal region engaged in emotional-cognitive interactions is generally hyperactivated.

Reduced anterior temporal and hippocampal functional connectivity during face processing discriminates individuals with social anxiety disorder from healthy controls and panic disorder, and increases following treatment

Group functional magnetic resonance imaging (fMRI) studies suggest that anxiety disorders are associated with anomalous brain activation and functional connectivity (FC). However, brain-based features sensitive enough to discriminate individual subjects with a specific anxiety disorder and that track symptom severity longitudinally, desirable qualities for putative disorder-specific biomarkers, remain to be identified. Blood oxygen level-dependent (BOLD) fMRI during emotional face perceptual tasks and a new, large-scale and condition-dependent FC and machine learning approach were used to identify features (pair-wise correlations) that discriminated patients with social anxiety disorder (SAD, N=16) from controls (N=19). We assessed whether these features discriminated SAD from panic disorder (PD, N=16), and SAD from controls in an independent replication sample that performed a similar task at baseline (N: SAD=15, controls=17) and following 8-weeks paroxetine treatment (N: SAD=12, untreated controls=7). High SAD vs HCs discrimination (area under the ROC curve, AUC, arithmetic mean of sensitivity and specificity) was achieved with two FC features during unattended neutral face perception (AUC=0.88, P<0.05 corrected). These features also discriminated SAD vs PD (AUC=0.82, P=0.0001) and SAD vs HCs in the independent replication sample (FC during unattended angry face perception, AUC=0.71, P=0.01). The most informative FC was left hippocampus-left temporal pole, which was reduced in both SAD samples (replication sample P=0.027), and this FC increased following the treatment (post>pre, t(11)=2.9, P=0.007). In conclusion, SAD is associated with reduced FC between left temporal pole and left hippocampus during face perception, and results suggest promise for emerging FC-based biomarkers for SAD diagnosis and treatment effects.

More than a face: a unified theoretical perspective on nonverbal social cue processing in social anxiety

Processing of nonverbal social cues (NVSCs) is essential to interpersonal functioning and is particularly relevant to models of social anxiety. This article provides a review of the literature on NVSC processing from the perspective of social rank and affiliation biobehavioral systems (ABSs), based on functional analysis of human sociality. We examine the potential of this framework for integrating cognitive, interpersonal, and evolutionary accounts of social anxiety. We argue that NVSCs are uniquely suited to rapid and effective conveyance of emotional, motivational, and trait information and that various channels are differentially effective in transmitting such information. First, we review studies on perception of NVSCs through face, voice, and body. We begin with studies that utilized information processing or imaging paradigms to assess NVSC perception. This research demonstrated that social anxiety is associated with biased attention to, and interpretation of, emotional facial expressions (EFEs) and emotional prosody. Findings regarding body and posture remain scarce. Next, we review studies on NVSC expression, which pinpointed links between social anxiety and disturbances in eye gaze, facial expressivity, and vocal properties of spontaneous and planned speech. Again, links between social anxiety and posture were understudied. Although cognitive, interpersonal, and evolutionary theories have described different pathways to social anxiety, all three models focus on interrelations among cognition, subjective experience, and social behavior. NVSC processing and production comprise the juncture where these theories intersect. In light of the conceptualizations emerging from the review, we highlight several directions for future research including focus on NVSCs as indexing reactions to changes in belongingness and social rank, the moderating role of gender, and the therapeutic opportunities offered by embodied cognition to treat social anxiety.

Altered neural correlates of affective processing after internet-delivered cognitive behavior therapy for social anxiety disorder

Randomized controlled trials have yielded promising results for internet-delivered cognitive behavior therapy (iCBT) for patients with social anxiety disorder (SAD). The present study investigated anxiety-related neural changes after iCBT for SAD. The amygdala is a critical hub in the neural fear network, receptive to change using emotion regulation strategies and a putative target for iCBT. Twenty-two subjects were included in pre- and post-treatment functional magnetic resonance imaging at 3T assessing neural changes during an affective face processing task. Treatment outcome was assessed using social anxiety self-reports and the Clinical Global Impression-Improvement (CGI-I) scale. ICBT yielded better outcome than ABM (66% vs. 25% CGI-I responders). A significant differential activation of the left amygdala was found with relatively decreased reactivity after iCBT. Changes in the amygdala were related to a behavioral measure of social anxiety. Functional connectivity analysis in the iCBT group showed that the amygdala attenuation was associated with increased activity in the medial orbitofrontal cortex and decreased activity in the right ventrolateral and dorsolateral (dlPFC) cortices. Treatment-induced neural changes with iCBT were consistent with previously reported studies on regular CBT and emotion regulation in general.

Brain activation during anticipatory anxiety in social anxiety disorder

Exaggerated anticipatory anxiety during expectation of performance-related situations is an important feature of the psychopathology of social anxiety disorder (SAD). The neural basis of anticipatory anxiety in SAD has not been investigated in controlled studies. The current study used functional magnetic resonance imaging (fMRI) to investigate the neural correlates during the anticipation of public and evaluated speaking vs a control condition in 17 SAD patients and 17 healthy control subjects. FMRI results show increased activation of the insula and decreased activation of the ventral striatum in SAD patients, compared to control subjects during anticipation of a speech vs the control condition. In addition, an activation of the amygdala in SAD patients during the first half of the anticipation phase in the speech condition was observed. Finally, the amount of anticipatory anxiety of SAD patients was negatively correlated to the activation of the ventral striatum. This suggests an association between incentive function, motivation and anticipatory anxiety when SAD patients expect a performance situation.

Amygdala activation and its functional connectivity during perception of emotional faces in social phobia and panic disorder

Social phobia (SP) and panic disorder (PD) have been associated with aberrant amygdala responses to threat-related stimuli. The aim of the present study was to examine amygdala function and its connectivity with medial prefrontal cortex (mPFC) during emotional face perception in PD and SP, and the role of illness severity. Blood oxygen level dependent responses while perceiving emotional facial expressions were compared in 14 patients with PD, 17 patients with SP, 8 patients with comorbid PD and SP, and 16 healthy controls. We found that PD, but not SP, was associated with amygdala and lingual gyrus hypoactivation during perception of angry, fearful, happy and neutral faces, compared to healthy participants. No significant effect of PD and SP diagnoses was found on amygdala-mPFC connectivity. A positive correlation of anxiety symptom severity was found on amygdala-dorsal anterior cingulate and dorsal mPFC connectivity during perception of fearful faces. Amygdala hypoactivation suggests reduced responsiveness to positive and negative emotional faces in PD. Symptom severity, but not the presence of PD and SP diagnosis per se, explains most of the abnormalities in amygdala-mPFC connectivity during perception of fearful faces.

Neuroimaging studies of pediatric social anxiety: paradigms, pitfalls and a new direction for investigating the neural mechanisms

Social Anxiety Disorder (SAD) is a common and debilitating condition that typically manifests in adolescence. Here we describe cognitive factors engaged by brain-imaging tasks, which model the peer-based social interactions that evoke symptoms of SAD. We then present preliminary results from the Virtual School paradigm, a novel peer-based social interaction task. This paradigm is designed to investigate the neural mechanisms mediating individual differences in social response flexibility and in participants' responses to uncertainty in social contexts. We discuss the utility of this new paradigm for research on brain function and developmental psychopathology.

Automatic neural processing of disorder-related stimuli in social anxiety disorder: faces and more

It has been proposed that social anxiety disorder (SAD) is associated with automatic information processing biases resulting in hypersensitivity to signals of social threat such as negative facial expressions. However, the nature and extent of automatic processes in SAD on the behavioral and neural level is not entirely clear yet. The present review summarizes neuroscientific findings on automatic processing of facial threat but also other disorder-related stimuli such as emotional prosody or negative words in SAD. We review initial evidence for automatic activation of the amygdala, insula, and sensory cortices as well as for automatic early electrophysiological components. However, findings vary depending on tasks, stimuli, and neuroscientific methods. Only few studies set out to examine automatic neural processes directly and systematic attempts are as yet lacking. We suggest that future studies should: (1) use different stimulus modalities, (2) examine different emotional expressions, (3) compare findings in SAD with other anxiety disorders, (4) use more sophisticated experimental designs to investigate features of automaticity systematically, and (5) combine different neuroscientific methods (such as functional neuroimaging and electrophysiology). Finally, the understanding of neural automatic processes could also provide hints for therapeutic approaches.

Amygdala functional connectivity in young women with borderline personality disorder

Borderline personality disorder (BPD) is a complex psychiatric disorder that involves the core feature of affect dysregulation. Prior neuroimaging studies have indicated that BPD patients have (1) excessive amygdala activation to negative emotion and (2) diminished frontal regulation. This study examined amygdala functional connectivity in 12 women with BPD and 12 matched healthy comparison volunteers. We explored how connectivity patterns would change in the context of processing neutral, overt fear, or masked fear face expressions. Each participant underwent three 5-min fMRI scans in which they primarily viewed: (1) neutral, (2) overt fear, and (3) masked fear faces. In comparison to their healthy counterparts, young women with BPD showed (1) lower connectivity between bilateral amygdala and mid-cingulate cortex during the neutral scan; (2) higher connectivity between bilateral amygdala and rostral anterior cingulate cortex during the overt fear scan; and (3) higher right amygdala connectivity with bilateral thalamus and right caudate during the masked fear scan. Exploratory analyses revealed interesting correlations between amygdala connectivity in these conditions with multiple clinical measures. Results from the neutral scan add to the few prior connectivity studies in BPD that have been suggestive of lower fronto-limbic connectivity in BPD. However, the connectivity findings during fear processing are novel, and map onto basic research models for amygdala connectivity, that is, connections to frontal areas for overt fear processing versus connections to thalamus for automatic fear processing. Further, results suggest that BPD subjects tap into both pathways more strongly than healthy comparisons.

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.

Amygdala responsiveness to emotional words is modulated by subclinical anxiety and depression

Several neuroimaging studies underlined the importance of the amygdala and prefrontal brain structures (e.g. dorsolateral prefrontal cortex [DLPFC]) for the processing of emotional stimuli and for emotion regulation. Many studies used visual scenes or faces as emotion-inducing material, and there is evidence that negative or positive words activate emotion-processing brain regions in the same way. However, no study so far focused on the influence of subclinical measures of anxiety or depression on the neural processing of emotional words. In this fMRI-study, we therefore investigated brain activation to emotional words in relation to subclinical measures of trait anxiety and depression in a sample of 21 healthy subjects. We also assessed effects of subclinical anxiety and depression on amygdala-prefrontal coupling during negative (versus neutral) word reading. Both negative and positive words activated the amygdala, and negative-word processing revealed a positive correlation between amygdala activity and scores of trait anxiety and subclinical depression. During negative versus neutral word reading, subjects with high trait anxiety also showed a stronger functional coupling between left amygdala and left DLPFC. These results suggest a modulation of negative-word processing by subclinical depression and anxiety, as well as possible prefrontal compensatory processes during unintentional emotion regulation in subjects with higher trait anxiety.

Affective engagement for facial expressions and emotional scenes: the influence of social anxiety

Pictures of emotional facial expressions or natural scenes are often used as cues in emotion research. We examined the extent to which these different stimuli engage emotion and attention, and whether the presence of social anxiety symptoms influences responding to facial cues. Sixty participants reporting high or low social anxiety viewed pictures of angry, neutral, and happy faces, as well as violent, neutral, and erotic scenes, while skin conductance and event-related potentials were recorded. Acoustic startle probes were presented throughout picture viewing, and blink magnitude, probe P3 and reaction time to the startle probe also were measured. Results indicated that viewing emotional scenes prompted strong reactions in autonomic, central, and reflex measures, whereas pictures of faces were generally weak elicitors of measurable emotional response. However, higher social anxiety was associated with modest electrodermal changes when viewing angry faces and mild startle potentiation when viewing either angry or smiling faces, compared to neutral. Taken together, pictures of facial expressions do not strongly engage fundamental affective reactions, but these cues appeared to be effective in distinguishing between high and low social anxiety participants, supporting their use in anxiety research.

Inflammation selectively enhances amygdala activity to socially threatening images

Although social withdrawal is a prominent symptom of sickness, the mechanisms associated with this behavioral change remain unclear. In animals, the amygdala is a key neural region involved in sickness-induced social withdrawal. Consistent with this, in humans, heightened amygdala activity to negative social cues is associated with social avoidance tendencies. Based on these findings, we investigated whether an experimental inflammatory challenge selectively increased amygdala activity to socially threatening images as well as whether this activity related to feelings of social disconnection. Thirty-nine participants were randomly assigned to receive either placebo or low-dose endotoxin, which increases inflammatory activity. Pro-inflammatory cytokines were assessed at 7 hourly time points via blood draws; self-reported feelings of social disconnection and physical sickness symptoms were assessed hourly as well. Two hours post-injection, participants underwent an fMRI procedure to assess amygdala reactivity during the presentation of socially threatening images (fear faces) as well as non-socially threatening images (guns), socially non-threatening images (happy faces), and non-social, non-threatening images (household objects). Endotoxin led to greater amygdala activity in response to socially threatening vs. all other types of images. No such differences were found for placebo participants. Additionally, increased amygdala activity in endotoxin participants during the viewing of socially vs. non-socially threatening images was associated with increased feelings of social disconnection. These findings highlight the amygdala as a neural region that may be important for sickness-induced social withdrawal. The implications of amygdalar involvement in sickness-induced social withdrawal are discussed.

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.