Nitrous Oxide Neuroimaging

After a no-drug control period, subjects will inhale nitrous oxide, administered via a breathing circuit and face mask, until a steady-state target end-tidal expired concentration is reached. During the drug condition, subjects will receive low-dose nitrous oxide (% corresponding to Minimum Alveolar Concentration).

Experimental acute pain stimulus will be delivered using a nerve stimulator. These painful shocks will be paired with a fixed number of the experimental cues, in a pattern that appears random to participants.