The purpose of this research study is to identify brain activation patterns in response to deep brain stimulation (DBS). To participate in this study, participants are required to have had a DBS implant or to be healthy controls without a history of a neurological disorder. Participants will undergo screening, a motor assessment session and a 30-minute Magnetic Resonance Imaging (MRI) session where their DBS device will be turned on and off in a cycled pattern. This study will be separated over 3 visits (Visit 1 for screening, Visit 2 for motor assessments and Visit 3 for the MRI scans). The total study duration will be approximately 5 hours.