The purpose of this study is to use an investigational device to record brain activity for 12-24 months following surgical implantation of deep brain stimulation (DBS) systems. The goal of the study is better understanding of brain activity in Parkinson's disease and how they relate to DBS and pharmacological management, not to bring new devices to market.

Experimental: chronic brain recording This is a one-arm, single-center study of the neurophysiology of human movement disorders with two goals: 1) Assess the feasibility of chronic brain recording using a novel fully implantable pulse generator (Medtronic Activa PC+S), which has the capability of sensing and storing local field potentials (LFPs) recorded from implanted electrodes, in addition to providing therapeutic deep brain stimulation (DBS). 2) Study acute and chronic effects of therapeutic DBS on cortical LFPs. 3) Study feasibility of the use of brain signals as feedback either directly to the patient or for DBS stimulation adjustments.

Inclusion Criteria:

1. Diagnosis of idiopathic Parkinson's Disease (PD).
2. Age 45-75 years
3. UPDRS III motor score (off PD medications) ≥ 25
4. Demonstrated good response (≥ 30%) to Sinemet or dopamine agonist medications as assessed by total UPDRS III score (off and on meds)
5. Approved for unilateral subthalamic nucleus (STN)- or globus pallidus internus (GPi)-DBS surgery to treat their clinical motor signs and plan to undergo the standard of care procedure within the next four months
6. Cleared to be scanned in a 7 tesla magnet
7. Written documentation of willingness to participate in the study per protocol as evidenced by the informed consent process

Exclusion Criteria:

1. Clinically significant medical disease that would increase the risk of developing pre- or post-operative complications (e.g., significant cardiac or pulmonary disease)
2. Evidence of secondary or atypical parkinsonism
3. Dementia as evidenced by impairment in two neuropsychological domains and impaired or borderline neuropsychological function in one additional domain.
4. Unable to undergo magnetic resonance imaging (e.g., due to incompatible implanted pacemaker)
5. Previous pallidotomy or DBS surgery
6. Women who are currently pregnant or are breast feeding
7. MRI showing cortical atrophy out of proportion to age and/or MRI showing focal brain lesions that could indicate a non-idiopathic movement disorder
8. Any prior intracranial surgery
9. Subjects with depression defined according to Diagnostic and Statistical Manual V criteria and a scored on a validated depression assessment scale
10. History of seizures
11. Immunocompromised
12. Requires diathermy, electroconvulsive therapy (ECT) or transcranial magnetic stimulation (TMS) to treat a chronic condition
13. Has an implanted electronic device such as a neurostimulator, cardiac pacemaker or medication pump.