Inclusion Criteria:  Patients undergoing selective awake craniotomies. Age ≥18 years. Obtain written informed consent.  Exclusion Criteria:  Preoperative severe cognitive impairment (Montreal Cognitive Assessment, MoCA< 18). History of psychotropic drugs. BMI≤18 or ≥30 Kg/mm2 Pregnant or lactating women. History of traumatic brain injury or neurosurgery. Severe bradycardia (heart rate less than 40 beats per minute), sick sinus syndrome or second-to-third degree atrioventricular block. Severe hepatic or renal dysfunction.