Background: In PTSD increased amygdala activity is found in parallel to decreased anterior cingulate activity and this imbalance relate to symptomatology. Consistently, in healthy controls enhanced vmPFC activity suppress fear conditioning and enhance extinction similar to reappraisal studies where dPFC activation supports emotional down regulation through amygdala attenuation. It is not established if phobic disorders display a similar pattern and if treatment induced changes affect “top-down” and/or “bottom-up” mechanisms.

Methods: Using a meta-analytical approach, we review brain-imaging studies using symptom provocation in patients with specific or social phobia as well as PTSD to evaluate reactivity in the ACC and the amygdala and its correlation to symptomatology. Further, amygdala ACC connectivity and the effect of CBT will be covered.

Results: Functional brain imaging studies reveal increased amygdala reactivity that is correlated with symptomatology across the anxiety disorders. In phobic patients enhanced ACC responsivity is observed. The correlation between symptomatology and prefrontal brain activity is consistently negative and ACC related in PTSD while in phobic patients the relation is positive and encompass prefrontal areas outside the ACC, particularly in SAD. Connectivity patterns suggest couplings between amygdala and PFC, limited to ACC in PTSD but not in phobic disorders. Finally, CBT-treatment is associated both with increased and decreased activity in the ACC and other prefrontal areas.

Conclusions: A tentative conclusion is that, even though the pattern of activity and connectivity both segregate and integrate different anxiety disorders, the ACC has a prominent role in coding and controlling affect.