The goal of this proposal is to provide therapy to patients with severe, treatment-refractory obsessive-compulsive disorder (OCD) by stimulating in two separate, but related, brain regions, the dorsolateral prefrontal cortex (dlPFC) and the ventral anterior limb of the internal capsule and adjacent ventral striatum (VC/VS) with a novel Medtronic PC+S deep brain stimulation (DBS) system. While providing this DBS therapy, use of this new, recording-capable device will allow collection of data about brain activity in these two regions. This data will enable researchers to further elucidate the exact mechanisms of DBS therapy, as well as the neuropathophyisiology of OCD. This study aims to 1) gather evidence for corticostriatal changes in OCD in response to acute and chronic VC/VS DBS treatment and 2) specifically disrupt or enhance synchrony in the cortico-striato-thalamo-cortical (CSTC) circuit.