Obsessive compulsive disorder as a functional interhemispheric imbalance at the thalamic level

Obsessive Compulsive Disorder (OCD) involves failures in two main inhibitory processes, namely cognitive
(obsessions) and behavioral (compulsions). Recent research has supported two cortical–subcortical
pathways on OCD pathogenesis: (a) the frontostriatal loop (dorsolateral-caudate–striatum–thalamus)
responsible for impairments of behavioral inhibition; (b) the orbitofrontal loop (orbitofrontal, medial prefrontal
and cingulate) responsible for impairments with cognitive inhibitory processes. These failures in
both cognitive and motor inhibitory systems may mediate several neuropsychological deficits in these
patients, namely memory, attention, planning and decision making. But are those deficits related to specific
hemispheric effects, namely functional imbalance between hemispheres? In this article we hypothesize
that: (1) OCD patients have an inter-hemispheric functional imbalance, probably due to inadequate
filtering at the thalamic level; (2) the restoration of inter-hemispheric balance, will be correlative to
symptomatic improvement.