This study will help us better understand how the brain works in people with Parkinson's disease (PD). PD is a brain disease that gets worse over time, and affects over 10 million people world-wide. A common treatment for PD is Deep Brain Stimulation (DBS). To improve DBS therapy for PD, we need a deeper understanding of how the different parts of the brain work together in PD, and how this relates to movement and thinking problems that people with PD experience. We may be able to use the results of this study to improve DBS treatments in the future.