Key Learning Point The two main sites for deep brain stimulation in Parkinson’s disease are the subthalamic nucleus and globus pallida interna. Explanation DBS is a treatment for Parkinson's disease. Treatment sites include the Globus pallidus interna and subthalamic nucleus. The subcallosal cingulate was the first target area investigated for DBS for treatment resistant depression (TRD). Vagal nerve stimulation has also been used for TRD. Targeting the anterior limb of the internal capsule is a psychosurgical treatment for refractory OCD and TRD. The caudate nucleus is part of the basal ganglia. Although associated with Parkinson's disease, it is not a primary treatment site for DBS.