Obsessive-compulsive disorder

Although neuroimaging has a limited role in the diagnostic assessment of obsessive-compulsive disorder (OCD), neuroimaging research has contributed crucial information regarding the pathophysiology of OCD and related diseases. OCD may be one of a spectrum of disorders that all involve corticostriatal pathology, in which the clinical presentation reflects the topography of dysfunction within the striatum. Structural neuroimaging studies of OCD have indicated volumetric abnormalities in the caudate nucleus. Functional imaging studies of OCD have shown increased activity in the corticostriatal pathway involving anterior orbitofrontal cortex and the caudate nucleus, both at rest and during symptom provocation, which is attenuated following effective treatment. Paralimbic elements, such as the anterior cingulate and posterior orbitofrontal cortex, may play a role in mediating anxiety or arousal nonspecifically. Taken together, these imaging data support the ''striatal topography'' model of OCD and suggest directions for future research, focusing on processes involving anterior orbitofrontal cortex and the caudate nucleus.