DOCK5 x GABAA receptor

The purpose of this study is to collect electrophysiological data related to functional brain network changes in patients undergoing deep brain stimulation for the treatment of essential tremor. Participants will be asked to remain seated with their head inside of a Magnetoencephalography (MEG) recording system as resting-state and task-related data are acquired. Spontaneous electrophysiological activity will be recorded in both the eyes open and eyes closed conditions with the participant seated comfortably. These recordings will be repeated in the DBS OFF and DBS ON states, with the ON state involving specific settings identified as optimal, sub-optimal, or ineffective at achieving tremor control. They will also be repeated following the optional administration non-DBS tremor mitigation techniques, which may include one or more of 1) cooling the limb, 2) oral administration of alprazolam, 3) oral consumption of ethanol (alcohol), or 4) peripheral nerve stimulation.

In this study, the investigators will measure affective, neurocognitive and behavioral outcomes related to chronic use of opioids and benzodiazepines (screening phase), and in response to the administration of the opioid morphine, the benzodiazepine alprazolam, morphine then alprazolam, alprazolam then morphine, morphine+alprazolam simultaneously, and placebo (laboratory pharmacology experiment). The latter will enable the investigators to assess the effects of an opioid alone, benzodiazepine alone, concurrent and simultaneous administration of opioid+benzodiazepine, relative to a placebo control.