ABSTRACT
Functional neuroimaging studies have implicated the frontal lobes and the hippocampus-amygdala complex in the pathophysiology of obsessive-compulsive disorder (OCD). Patients with OCD had significantly reduced bilateral orbital frontal and amygdala volumes compared with healthy comparison subjects and lacked the normal hemispheric asymmetry of the hippocampus-amygdala complex. Abnormalities in the mesiotemporal lobe may also be important in understanding the repetitive thoughts and behaviors associated with OCD. Amygdalocentric models of OCD are particularly relevant given the amygdala’s involvement in the emotional appraisal of external stimuli and the acquisition and consolidation of conditioned fear and anxiety responses. Measurement of mesiotemporal lobe structures was based on criteria opera tionalized from postmortem histological work using a semi-automated, computerized mensuration system.
