This study focuses on a treatment for Parkinson's disease, which affects movements. It involves a procedure called Subthalamic Nucleus Deep Brain Stimulation (STN-DBS). During the procedure, small electrodes are placed in the brain to help control movement. Sometimes patients need to be awake for this, using a sedative called Dexmedetomidine. The study tests if adding another drug, Esketamine, can improve the process without affecting brain signals.

Participants will be split into two groups: one receives Dexmedetomidine, and the other gets Dexmedetomidine with Esketamine. The study checks how these drugs affect brain signals during surgery, sleep after surgery, and mood changes like depression and anxiety.

• The study requires patients to be aged 50-80 and have Parkinson's.
• Participants will not know which drug group they are in (double-blind).
• Key risks include potential sleep apnea, serious organ issues, or severe anxiety.

Understanding these effects can help improve treatment for Parkinson's patients during this brain surgery.