Deep Brain Stimulation (DBS) is an FDA approved, and widely used method for treating the motor symptoms of Parkinson's Disease (PD), Essential Tremor (ET) and Dystonia. Over 100,000 patients worldwide have now been implanted with DBS devices. The DBS target regions in the brain are the Subthalamic nucleus (STN), the Internal Segment of Globus Pallidus (GPi), or the Ventral Intermediate Nucleus of the Thalamus (VIM). In order to place the DBS electrode in the target location, a combination of two 3D imaging techniques; 3D MRI and CT, are used. Data are also collected from individual nerve cells to help find the best location for the DBS electrode in each patient. This electrode recording takes place during the standard surgical implantation of the DBS electrode, and is part of the standard clinical technique. The investigators plan to collect additional data from populations of neurons during the DBS surgery in an effort to further improve the placement of the DBS electrode. These "Local Field Potentials", LFPs, represent the activity of the collection of neurons surrounding the tip of the electrode, and will be measured during surgery along the path used for the placement of the DBS electrode. The goal of this project is to determine whether this additional data from surrounding neurons will help with optimal placement of the DBS electrode.

Inclusion Criteria:

• Subjects included in this study will be those who are planning to undergo DBS surgery because of their underlying idiopathic Parkinson's disease, Essential Tremor, or Dystonia--all FDA-approved indications for the implantation of DBS devices.

Exclusion Criteria:

• Subjects with the most advanced symptoms of PD (stage V in the Hoehn and Yahr rating scale).
• Subjects who are not planning to undergo DBS surgery.
• Subjects not candidates for DBS surgery based on clinical criteria.

Movement disorder patients from primary care clinic.