With regard to the cortex, prior magnetic resonance imaging (MRI) studies consistently show abnormalities in dorsomedial prefrontal and anterior cingulate cortices (ACC) (7–10), findings that are supported by mega-analyses from the OCD Brain Imaging Consortium (11; 12). Also abnormalities in fronto-parietal and temporo-parietal regions have been reported (10; 12–14). Findings regarding the orbitofrontal cortex (OFC) (8; 11; 15) and operculum have been rather inconsistent (8; 10; 11; 13; 16). These inconsistencies may be partially explained by differences in processing protocols, limited statistical power, and clinical heterogeneity related to variation in disease profile and developmental stage.
