Furthermore, although CSTC circuits have been most extensively studied and related to the neurobiology of OCD, other structures also appear to be relevant. For example, recent work highlights the importance of dysfunction in connectional “hub” regions in a range of disorders [180–183]. “Hubs” are regions characterized by particularly dense connections with other brain regions and as such are crucial for the efficient function of neurocircuits [184]. Hub regions include, among others, the inferior parietal lobule, which is strongly connected with frontal and subcortical regions and critically involved in mediating attention, particularly attentional bias towards disease-relevant stimuli (such as threatening images), and may represent a key transdiagnostic region of dysfunction and a treatment target for OCD and anxiety disorders [180–181]. Indeed, a large multisite consortium study (ENIGMA, [185]) revealed thinner inferior parietal cortex in OCD patients compared to non-psychiatric volunteers [186]. Other hub regions include the cingulum, anterior insula, anterior cingulate cortex (ACC) and dorsal striatum [182–184], which are involved in several of the circuits discussed here. These hub regions appear to be involved in many self-regulatory control functions, including cognitive
