This article is intended to elucidate some of the neuropathogenetic
mechanisms possibly operative in obsessive-compulsive disorder (OCD).
Relevant literature is reviewed, with attention to psychologic, and
pathologic considerations. Anatomy, neurochemistry, and known functional
associations with neuropathological and behavioral abnormalities of
implicated brain regions are discussed. The authors propose that
dysfunction of neuronal circuits interconnecting the orbitofrontal cortex,
basal ganglia/limbic striatum, and thalamus serves a critical role in the
pathogenesis of OCD and that obsessive- compulsive symptoms occur when an
aberrant positive feedback loop develops in the reciprocally excitatory
frontothalamic neuronal interchange, which is inadequately integrated or
inhibited by the ventromedial (limbic) portions of the striatum; the
ventromedial striatum may serve to modulate activity in the frontothalamic
circuit through a negative feedback loop.