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.