Motor Cortex Reward Signaling in Parkinson Disease

Study Summary

Background: The brain releases signals to mark rewards for certain behavior. Some medications for Parkinson disease (PD) can cause some patients to engage in compulsive behavior, possibly because the medications affect this reward system. By using transcranial magnetic stimulation (TMS), researchers can study brain activity when an individual receives a reward. Objectives: To learn how the brains of people with PD behave when rewarded. To learn whether two common Parkinson medications (levodopa and pramipexole) change this behavior. To compare reward signals in the brains of healthy volunteers with reward signals in the brains of people with PD. Eligibility: Women between 50 and 80 years of age and men between 45 and 80 years of age. Participants will be divided into healthy volunteers and volunteers who have mild to moderate PD. Design: Prescreening will consist of a neurological examination and a series of questions about gambling habits and drug and alcohol use. Participation in a TMS study involving a computer game simulation of a slot machine: * Before the simulation, participants will receive TMS to establish a baseline response rate. * During the simulation, participants will play a game in which they will receive real money. TMS will be administered to each patient under three different conditions: * TMS administered when patients have not taken any Parkinson medication. * TMS administered after patients have taken levodopa. * TMS administered after patients have taken pramipexole....