Neural Correlates of Hypoalgesia Driven by Observation

"4mg of Naloxone will be administered (0.1 mL of 40 mg/ml naloxone solution given intranasally).~A random allocation sequence will be independently generated by the UM Pharmacy. The Principal investigator will call for each experiment."

"Intranasal Normal Saline (0.1 mL 0.9% sodium chloride) will be administered shortly before beginning the fMRI experiment.~A random allocation sequence will be independently generated by the UM Pharmacy. The Principal investigator will call for each experiment."