All patients will be tested with the moral and the economics tasks during the best ON-drug medication condition. The experimental group performed the tasks in the STN DBS ON condition and in the STN DBS OFF condition. Following the end of the STN DBS ON session, the DBS devices will be turned off by the physician 30 minutes prior to the STN DBS OFF session. The order of stimulation conditions and of the versions of the task will be randomized and counterbalanced.