This study is investigating the usefulness of using functional magnetic resonance imaging (fMRI) to monitor brain activation during deep brain stimulation for Parkinson's Disease, Essential tremor, dystonia, OCD, depression, pain, Tourette's syndrome, and epilepsy. The study may determine the relationship between patterns of brain activation and therapeutic outcome and/or side effects.

Deep brain stimulation (DBS) is an effective neurosurgical approach for treating motor disorders including Parkinson's disease (PD), Essential Tremor (ET), and dystonia. Its therapeutic benefit has led to the application of DBS to a wide spectrum of disorders including psychiatric conditions, epilepsy, Alzeimer's disease, headache, obsessive-compulsive disorder (OCD), Tourette syndrome, depression and intractable pain. However, because the nature of its underlying mechanisms and clinical effects are not fully understood, precision targeting, decreasing adverse effects, and improving clinical outcomes represent major clinical and scientific challenges in PD and other disorders treated by DBS. Our goal is to investigate the inter-relationships between site-specific neural activation and clinical outcomes during DBS. To do so, we will perform non-invasive functional Magnetic Resonance Imaging (fMRI) to investigate DBS-mediated activation of neural network circuitry. Our proposed protocol involves the addition of intraoperative fMRI to the standard DBS or battery change protocol in order to determine the major sites of activation during application of clinically effective DBS to the subthalamic nucleus (STN), ventral intermediate thalamus (VIM), globus pallidus interna (GPi), fornix, nucleus accumbens (NAc), anterior thalamus and periaqueductal gray matter. Patients will undergo clinical assessment to determine the relative efficacy of DBS stimulation parameters, applied during the fMRI and at regularly scheduled post-operative programming visits up to 6 months of follow-up. Our Specific Aims are to: (1) Identify fMRI-activated brain regions by DBS in patients who undergo DBS surgery (Patients diagnosed with PD, ET, dystonia, OCD, depression, pain, Tourette's syndrome, and epilepsy. (2) Correlate fMRI activation with clinical outcomes and side effects. With the goal of improving DBS electrode targeting for optimal and reproducible clinical outcomes, these experiments will be the first attempt to relate site-specific DBS with functional in vivo imaging data and quantitative longitudinal clinical outcome measures in DBS patients.

Inclusion Criteria:

• Adult Patients with medically intractable Parkinson's Disease who have been approved for DBS surgery by the interdisciplinary Mayo DBS committee.

Exclusion Criteria:

• Pregnant patients, prisoners, children (age less than 18), and any patients identified as unsuitable for this protocol by the Mayo DBS committee.

Patients approved and scheduled to undergo the clinical procedure of Deep Brain stimulation.