Background: \- Deep brain stimulation (DBS) is an approved surgery for certain movement disorders, like Parkinson's disease, that do not respond well to other treatments. DBS uses a battery-powered device called a neurostimulator (like a pacemaker) that is placed under the skin in the chest. It is used to stimulate the areas of the brain that affect movement. Stimulating these areas helps to block the nerve signals that cause abnormal movements. Researchers also want to record the brain function of people with movement disorders during the surgery.

Objectives: * To study how DBS surgery affects Parkinson s disease, dystonia, and tremor. * To obtain information on brain and nerve cell function during DBS surgery.

Eligibility: \- People at least 18 years of age who have movement disorders, like Parkinson's disease, essential tremor, and dystonia.

Design: * Researchers will screen patients with physical and neurological exams to decide whether they can have the surgery. Patients will also have a medical history, blood tests, imaging studies, and other tests. Before the surgery, participants will practice movement and memory tests. * During surgery, the stimulator will be placed to provide the right amount of stimulation for the brain. Patients will perform the movement and memory tests that they practiced earlier. * After surgery, participants will recover in the hospital. They will have a followup visit within 4 weeks to turn on and adjust the stimulator. The stimulator has to be programmed and adjusted over weeks to months to find the best settings. * Participants will return for followup visits at 1, 2, and 3 months after surgery. Researchers will test their movement, memory, and general quality of life. Each visit will last about 2 hours.