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.

For this study, we are recruiting 54 individuals with Parkinson's Disease and Freezing of Gait (FOG) who are planning to undergo Deep Brain Stimulation (DBS). The objective of this study is to better understand the FOG response to DBS. Prior to DBS study participants will undergo a MRI scan, behavioral assessment related to walking, a cognitive evaluation, and assessment of other Parkinson's disease symptoms. Following DBS participants will repeat these assessments at multiple timepoints over the period of one year. Overall, participants will complete a total of 7 visits over a period of approximately 1 year.