Amygdala Volume and Social Anxiety Symptom Severity: A Mutli-method Study

Neuroimaging research has strongly influenced a biologically-based conceptualization of social anxiety, which is the fear of evaluation from others. Functional neuroimaging research has shown consistently a robust association between atypical amygdala activation and social anxiety symptoms. However, there are disparities in the small structural imaging literature on the amygdala and social anxiety. The inconsistent findings may, in part, be a function of differences across studies in the methods used to obtain amygdala volumes. Freesurfer and manual tracings are two common segmentation techniques, and the use of one over the other involves different tradeoffs. The present study directly compared amygdala volumes generated based on Freesurfer’s boundaries to those generated based on manually corrected boundaries, in neurotypical adults with varying levels of social anxiety. Also, it examined whether amygdala volume predicted social anxiety symptom severity. The Liebowitz Social Anxiety Scale – Self-Report version served as a measure of social anxiety. Participants (N = 76) were selected from three larger archival projects. They had social anxiety scores ranging from 0 - 108 (M = 54.59 ± 33.34). The results suggest Freesurfer’s boundaries consistently produced larger amygdala volumes than manually corrected boundaries. However, in neurotypical individuals with and without social anxiety, manual correction did not provide added benefit over the use of Freesurfer with regard to predicting social anxiety symptoms. The present findings strongly suggest that volumetric measurement of the amygdala is not helpful for understanding variability in social anxiety symptom severity and call into question numerous aspects of existing volumetric studies of the neural correlates of social anxiety

The psychological and neurobiological determinants of social behavior:Assessing the affective, cognitive, and neural processes underlying trust and mentalizing

Much remains unknown about the specific affective, cognitive, and neural mechanisms involved that support our social behavior. The gap is addressed in my doctoral research in two ways: 1) by investigating the relationship between integral affect and social economic decisions and 2) by delineating how incidental affect impacts the neural signature of mentalizing. We first conduct a literature review and meta-analysis to inform the current debate concerning the determinants of trust. Our critical review shows that many experimental paradigms fall short of identifying clear affective mechanisms involved in trust. Therefore, we developed a novel experimental approach that relate the affective and cognitive reactions to betrayal to participants’ decision in the trust game and the dictator game. The results show that betrayal is positively and specifically associated with trust. Moreover, the perception of how socially distant we are from our interaction partners is significantly associated with trust. To assess the influence of incidental affect on the mentalizing network, we conducted an fMRI experiment using a novel false-belief task. The results revealed that activity in bilateral TPJ and IFG reflect false belief processing, and, at the same time as confirmed by conjunction analysis, suppressed by anxiety. During belief inferences threat specifically suppressed belief-based connectivity between putamen and its targets in IPS and dlPFC, and dispositional distress significantly modulated threat-related suppression of connectivity between the left TPJ seed and left IPS. These findings highlight the effects of both incidental and dispositional anxiety on specific nodes of the social cognition network