The role of the basal ganglia in the processing of information with emotional or motivational content has been demonstrated by several lesion and functional imaging studies in humans and animals. Deep brain stimulation surgery provides an opportunity to study these structures in humans in electrophysiological terms. The aim of this study is to investigate modifications in the electrophysiological activity of the subthalamic nucleus (STN) during the perception of auditory and visual stimuli with emotional or motivational connotations in patients with Parkinson's disease who have just undergone implantation of a deep brain stimulator in the STN.

Inclusion Criteria:

• Patient with Parkinson's disease selected for deep brain stimulation (DBS) of the subthalamic nucleus (STN) in accordance with the criteria established by Welter and colleagues (Welter et al., 2002);
• Aged 18 years or above;
• Written informed consent from the patient.

Exclusion Criteria:

• Patient under a legal incapacity or with limited legal capacity;
• Patient who has perioperative complications or postoperative confusion;
• Patient displaying cognitive disturbances involving the early stages of speech processing (on the basis of an audiogram systematically conducted prior to surgery) ;
• Patient displaying cognitive disturbances involving the early stages of face processing (on the basis of the Benton Facial Recognition Test (Benton, Hamsher, Varney, & Spreen, 1983) systematically administered prior to surgery);
• Patient incapable of understanding the information given about the study, performing the tasks or providing informed consent.