A Study of Human Multi-Sensory Integration

Inclusion Criteria:

* Healthy volunteers ages 18-65 years old
* American Society of Anesthesiologists (ASA) Physical Status I or II (i.e. healthy)
* Body Mass Index \<30 kg/m2
* Easily visible uvula

Exclusion Criteria:

* Contraindications to administration of either propofol or ketamine
* Allergy to either one of the medications or preservative in which it is diluted.
* History (or current) seizure disorder
* Contraindications to anesthesia
* Significant cardiovascular disease (e.g. h/o hypertension, arrhythmias, myocardial infarction, congestive heart failure, congenital heart defects, coronary artery disease)
* Increased risk factors for difficult intubation and/or ventilation
* Obesity (BMI\>=30 kg/m2)
* Mallampati class \> 2.
* History of or current obstructive sleep apnea.
* Increased risk of aspiration
* Any per oral intake within 8 hours of anesthetic exposure
* Conditions that delay gastric emptying (e.g. obesity, hiatal hernia, gastro esophageal reflux disease, pregnancy, etc.)
* Pulmonary disease (e.g. chronic obstructive pulmonary disorder, asthma requiring rescue inhaler within last month, emphysema, pulmonary hypertension, pulmonary fibrosis etc).

  * Neurological disease. Patients with history of strokes, seizures, brain surgery, brain tumor, increased intracranial pressure.
  * Psychiatric disease. History of or presents of psychosis, schizophrenia, schizo-affective disorder.
  * Specific Medication Current Use. History of or current intake of antipsychotics or sedatives.
  * Drug abuse. History of or current use of illegal drugs such as stimulants or depressants.
  * Pregnancy or breastfeeding
  * Inability to provide informed consent