Deep brain stimulation is commonly used for the treatment of movement disorders. Electrode positioning is usually performed under local anesthesia in fully awake patients. The procedure is uncomfortable to the patients who has to remain motionless during the whole surgery. Previous reports of electrode positioning under general anesthesia was found to be less accurate. This result was probably due to the effect of the anesthetics on the electrical activity of the basal ganglia.

The purpose of this study is to detect possible changes in the electrical activity of the basal ganglia related to remifentanil sedation. electrical activity of single neurons will be recorded before, during and after sedation.

Inclusion Criteria:

• Patients with movement disorder, who are candidates for implantation of deep brain stimulation electrode.

Exclusion Criteria:

• Suspected difficult intubation
• history of sleep apnea
• known allergy for remifentanil