Patients who meet the enrollment criteria and voluntarily join this study will be admitted to the operating room on the day of surgery, and will receive endotracheal intubation under general anesthesia. Induction will be conducted with sufentanil 0.2~0.3ug/kg, rocuronium bromide 0.6mg/kg and propofol 1~2 mg/kg. After successful intubation, mechanical ventilation will be provided with a fresh air flow of 2.0 L/min, a tidal volume of 6~8ml/kg and a respiratory rate of 10~12 times/min to control the end-tidal carbon dioxide between 35~45mmHg. Following that, 20 ml of 0.5% ropivacaine will be applied for bilateral scalp nerve block. The surgeon will then install the stereotactic head frame and take the patients out for CT examination. After returning to the operating room after CT examination, the surgeons will install driving electrodes. During this period, GA will be maintained with sevoflurane, propofol, remifentanil and rocuronium bromide. The depth of anesthesia is monitored using BIS, with a target of 40-65.

During electrode implantation stage: sevoflurane, propofol and rocuronium bromide will be stopped, and esketamine 0.2~0.5mg/kg/h combined with remifentanil 0.5~1ug/kg/min will be used to maintain anesthesia with a target BIS value of 60-70. Patients' blood pressure and heart rate will be controlled to change within less than 30% of the basal value with necessary medication.

If the patient moves during the electrode implantation stage, the rescue plan is to quickly inhale sevoflurane to 0.3 mac, and the number of rescues will be recorded. The vital signs of the patient, MER signal strength, STN discharge frequency, length of STN localization nucleus, and whether the STN boundary is successfully located will be recorded.

During the implantation stage of the pulser, the GA regimen will return to before electrode implantation stage. In other words, sevoflurane + remifentanil + propofol + rocuronium bromide will be used to maintain the depth of anesthesia till the end of the operation.

Inclusion Criteria:

• Bilateral STN-DBS surgery is planned for primary PD (meeting the International Movement Disorder Society (MDS) diagnostic criteria for PD);
• ASA Classes I-III;
• Age 50-75 years;
• Informed consent from patients or their families

Exclusion Criteria:

• BMI≥28.0kg/m2；
• comorbid other conditions causing parkinson-like motor symptoms;
• Previous history of severe head trauma, deformity, or craniocerebral surgery;
• Previous history of psychiatric and neurological diseases, such as history of overt stroke (ischemic lesion near STN), depression, severe central nervous system depression, basal gangliopathy, schizophrenia, epilepsy, Alzheimer's disease, myasthenia gravis, etc.;
• Preoperative MoCA scale showed that the patient had dementia;
• Severe heart, liver, lung, kidney, and immune system diseases;
• Allergy or contraindication to the trial drug