One study showed that unmedicated subjects with obsessive compulsive disorder (OCD) had a hyperconnection of the orbitofrontal cortex and the basal ganglia. On the other hand, when subjects with OCD were medicated with antidepressants, there was reduced connectivity of the ventral striatum compared to unmedicated subjects. This interesting research highlights the abnormalities in the cortico-striato-thalamo-cortical circuits in OCD, and how antidepressants may correct the abnormalities (Beucke et al., 2013).
So OCD affects the orbitofrontal cortex and the basal ganglia.
