Ketamine and Propofol NeuroImaging

Inclusion Criteria: * Adults 18-59 years of age, who: * have none of the specific exclusion criteria * have a valid email address and valid phone number throughout the study * free from any non-MRI compatible implants Exclusion Criteria: * are pregnant or attempting to conceive * body mass index (BMI) \> 35 * significant memory impairment or hearing loss * sleep apnea * chronic pain or frequently taking pain medication * chronic medical conditions requiring treatment (hypertension, diabetes, high cholesterol) * neurologic disease, including seizures and tremor * psychiatric diagnoses, including anxiety, depression, panic, or PTSD * a history of any of these medical conditions: abnormal heartbeats (cardiac conduction abnormality or arrhythmia), liver or kidney disease, or significant lung disease * severe claustrophobia or intolerance of an MRI * have metal implants or non-removable metal piercings * having a history of adverse reaction to ketamine or propofol * daily alcohol or heavy alcohol use; history of alcohol abuse * current daily smoker * regular or recent marijuana use (including prescribed/medical marijuana) * illicit drug use, i.e., street drugs * regularly taking: antiepileptics, antidepressants, anti-psychotics, antihistamines, anti-anxiety medication, stimulants, or sleep-aids