The study designed to explore the efficacy and safety of the closed loop of target controlled infusion dexmedetomidine combined with propofol for anesthesia with intraoperative wake up.

Inclusion Criteria:

• Written informed consent.
• Ongoing brain functional area surgery with intraoperative wake up.
• American Society of Anesthesiologists class I to II.
• Aged between 18 and 65 years old.
• Weight between plus or minus 20% of the standard weight. Male: (height cm - 80) × 70% = standard weight Female: (height cm - 70) × 60% = standard weight

Exclusion Criteria:

• History of hypertension.
• Serious heart,brain,liver,kidney, pulmonary, and endocrine disease or serious infection.
• Mental disability or mental disease.
• Use of sedative drug.
• Suspected or confirmed long term use of narcotic analgesics.
• Inability to exchange.
• Suspected or confirmed difficult airway.
• Suspected of malignant hyperthermia.
• Neuromuscular disease.
• Allergic to investigational products or with other contraindication.
• Subjects who are breastfeeding or pregnant.
• Participated in other study within 30 days .