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Generalized social anxiety disorder (GSAD) is characterized by aberrant patterns of amygdala-frontal connectivity to social signals of threat and at rest. The neuropeptide oxytocin (OXT) modulates anxiety, stress, and social behaviors. Recent functional neuroimaging studies suggest that these effects are mediated through OXT's effects on amygdala reactivity and/or amygdala-frontal connectivity. The aim of the current study was to examine OXT's effects on amygdala-frontal resting-state functional connectivity (rsFC) in GSAD patients and healthy controls (HCs). In a randomized, double-blind, cross-over design, 18 GSAD and 18 HC participants received intranasal OXT (24 IU or 40.32 μg) or placebo (PBO) before resting-state functional magnetic resonance imaging. In individuals with GSAD, OXT enhanced rsFC of the left and right amygdala with rostral anterior cingulate cortex (ACC)/medial prefrontal cortex (mPFC), and in doing so, reversed (ie, 'normalized') the reduced amygdala-frontal connectivity observed relative to HCs evident on PBO. Higher social anxiety severity in GSAD subjects correlated with lower amygdala-ACC/mPFC connectivity on PBO and higher social anxiety also correlated with greater enhancement in amygdala-frontal connectivity induced by OXT. These findings show that OXT modulates a neural circuit known for social threat processing and emotion regulation, suggesting a neural mechanism by which OXT may have a role in the pathophysiology and treatment of social anxiety disorder.

Cognitive behavioral therapy (CBT) is “gold standard” psychotherapy for social anxiety disorder (SAD). Cognitive models posit that preferential processing of threat mediates excessive forms of anxiety, which is supported by exaggerated amygdala, insula, and cortical reactivity to threatening socio-emotional signals in SAD. However, little is known about neural predictors of CBT success or the mechanisms by which CBT exerts its therapeutic effects. Functional magnetic resonance imaging (fMRI) was conducted during responses to social signals of threat (fearful/angry faces) against positive signals (happy faces) in 14 patients with SAD before and after 12 weeks of CBT. For comparison, 14 healthy control (HC) participants also underwent two fMRI scans, 12 weeks apart. Whole-brain voxel-wise analyses showed therapeutic success was predicted by enhanced pre-treatment activation to threatening faces in higher-order visual (superior and middle temporal gyrus), cognitive, and emotion processing areas (dorsal anterior cingulate cortex, dorsomedial prefrontal cortex). Moreover, a group by time interaction was revealed in prefrontal regions (dorsomedial, medial gyrus) and insula. The interaction was driven by relatively greater activity during threat processing in SAD, which significantly reduced after CBT but did not significantly predict response to CBT. Therefore, pre-treatment cortical hyperactivity to social threat signals may serve as a prognostic indicator of CBT success in SAD. Collectively, CBT-related brain changes involved a reduction in activity in insula, prefrontal, and extrastriate regions. Results are consistent with cognitive models, which associate decreases in threat processing bias with recovery.

The ability to process and respond to emotional facial expressions is a critical skill for healthy social and emotional development. There has been growing interest in understanding the neural circuitry underlying development of emotional processing, with previous research implicating functional connectivity between amygdala and frontal regions. However, existing work has focused on threatening emotional faces, raising questions regarding the extent to which these developmental patterns are specific to threat or to emotional face processing more broadly. In the current study, we examined age-related changes in brain activity and amygdala functional connectivity during an fMRI emotional face matching task (including angry, fearful and happy faces) in 61 healthy subjects aged 7–25 years. We found age-related decreases in ventral medial prefrontal cortex (vmPFC) activity in response to happy faces but not to angry or fearful faces, and an age-related change (shifting from positive to negative correlation) in amygdala-anterior cingulate cortex/medial prefrontal cortex (ACC/mPFC) functional connectivity to all emotional faces. Specifically, positive correlations between amygdala and ACC/mPFC in children changed to negative correlations in adults, which may suggest early emergence of bottom-up amygdala excitatory signaling to ACC/mPFC in children and later development of top-down inhibitory control of ACC/mPFC over amygdala in adults. Age-related changes in amygdala-ACC/mPFC connectivity did not vary for processing of different facial emotions, suggesting changes in amygdala-ACC/mPFC connectivity may underlie development of broad emotional processing, rather than threat-specific processing.