Studies consistently show that both the dorsal/ventral ACC and medial PFC are recruited during the fear response. With regards to SAD, the ACC/mPFC complex is most likely associated with the evaluation of social feedback and conflict resolution. Individuals with lower self-esteem, who also tended to score higher on the STAI, showed hyperactivation of the ventral ACC/mPFC in response to positive social feedback. Activation of the dorsal ACC/mPFC was also observed during cognitive reappraisal. Taken together, these findings suggest a potential protective role of the ACC/mPFC complex against common symptoms of SAD.

Interactions between ACC and PFC in SAD

The prefrontal cortex (PFC) spans the anterior portion of the frontal lobe and is involved in a wide range of cognitive and executive functions. With regards to anxiety, the right PFC is highly activated in response to negative affect, particularly when their specific type of anxiety was triggered (i.e. social phobics being asked to give a speech). For SAD, studies have found strong connections between the PFC and anterior cingulate cortex.

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- Amygdala
- Insula
- Prefrontal cortex
- Anterior cingulate cortex

Brain Regions Involved in SAD

Davidson, R. J. (2002). Anxiety and affective style: Role of prefrontal cortex and amygdala. Biological Psychiatry, 51(1), 68–80. https://doi.org/10.1016/s0006-3223(01)01328-2

Anxiety and affective style: role of prefrontal cortex and amygdala (2002)

The insula is deeply connected to the amygdala, and both regions display activation in response to processing negative emotional stimuli. Hyperactivity in the insula has been found in individuals with SAD, specific phobias, and PTSD.

When individuals with SAD were tasked with giving an impromptu speech about a randomly generated topic, they demonstrated an increased activation in the right insula compared to healthy controls. This hyperactivity was correlated with self-reported increases in unpleasantness, arousal, and anxiety following the anticipation of giving the speech.

Insula and SAD

The amygdala is involved in threat detection, processing of emotional stimuli, and generating a fear response to said threat or negative stimulus. Neuroimaging studies show increased amygdalar activation in individuals with symptoms of social anxiety following the anticipation of, and subsequent exposure to, aversive images (as determined by the International Affective Picture System). Additionally, individuals with SAD demonstrated hyperactivity in the amygdala when tasked with giving an impromptu speech. Increased activity in the amygdala is therefore associated with symptoms of SAD, namely the fear of aversive social situations.

Amygdala and SAD

The anterior cingulate cortex (ACC), as part of the limbic system, is involved in emotional regulation. Specifically, the dorsal, or cognitive, ACC is involved in conflict resolution, while the rostral, or affective, ACC is involved in determining the valence of emotional stimuli. Individuals with social phobia show increased activation of the ACC when viewing "disgusted" facial expressions as opposed to neutral expressions. These individuals also rated the expressions as more negative, with a faster response time than healthy controls. Cingulectomy was shown to significantly improve symptoms in patients with anxiety neurosis. Taken together, these findings suggest a role for the rostral ACC in the pathology of SAD.

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