Structural Abnormalities of Frontal Neocortex in Obsessive-compulsive Disorder

Abstract

In the July 1996 issue of the ARCHIVES, Jenike et al¹ presented results from a morphometric magnetic resonance imaging (MRI)–based brain segmentation study of obsessive-compulsive disorder (OCD). Compared with normal controls, patients with OCD had significantly less total white matter (extending previous findings of decreased posterior white matter in a separate cohort of patients²), greater total neocortex, and greater opercular volumes. Furthermore, clinical severity of OCD and nonverbal immediate memory correlated with opercular cortical volume.¹ Several morphometric studies have found caudate volumetric abnormalities in OCD^1,3,4; however, comprehensive parcellation of neocortex has not been reported. Functional neuroimaging studies of OCD have primarily implicated orbitofrontal and anterior cingulate cortex, as well as striatum, with reports of hyperactivity during neutral states that is accentuated during symptom provocation and attenuated with treatment.⁵ As a complement to these imaging findings, a recent neuropsychological study has reported evidence of a nonverbal memory retrieval deficit with normal verbal and nonverbal memory storage in OCD.⁶ To our knowledge, there have been no morphometric studies to date linking prefrontal cortex to behavioral or neuropsychological indices in OCD.