Deep brain stimulation (DBS) of the Globus Pallidus interna (GPi) and the subthalamic nucleus (STN) is a current surgical technique for the treatment of movement disorders such as those in Parkinson’s disease (PD) and dystonia. During GPi DBS and pallidotomy eye movement impairments were reported: conjugate eye deviation, ocular fixation and saccade movement disturbance. The basal ganglia are well known to influence eye movement through action of the caudate nucleus, the STN and the subtantia nigra reticulata, but little is known about the GPi. The GPi is the main output of the basal ganglia (BG) that has been extensively explored for movement and behavioral controls. However, recent experimental studies in monkeys have shown the existence of GPi neurons modulating their activity in relation to saccade, suggesting that GPi might be involved in saccade control loops. This hypothesis could be consistent with clinical observations. We hypothesized that direct visual input into the Gpi could be detected using diffusion tensor imaging (DTI) and fiber tracking (FT); these fibers could belong to the supraoptic commissural system (Ganser, Meynert, Gudden).