Exploration of the Reward System by Functional MRI in Parkinson's Disease Patients With and Without REM Sleep Behavior Disorder

Up to 60% of Parkinson's Disease (PD) patients suffer from REM sleep behavior disorder (RBD), a parasomnia. This disorder is thought to be related to a dysfunction of limbic system and brainstem. Impulse control disorders (ICD) are found in about 14% of PD patients taking dopaminergic drugs. These disorders are thought to be related to a dysfunction of meso-cortico-limbic pathways which belong to the so-called "reward system". A strong link was found between these two disorders and therefore the investigators believe that RBD is associated with impaired reward system. The main objective of this study is to evaluate differences in brain activation between PD patients with and without RBD. The investigators hypothesize that PD patients with RBD have a more severe dysfunction of the reward system (hypoactivation of the meso-cortico-limbic pathway) than patients without RBD, explaining their susceptibility to ICD when exposed to high doses of dopaminergic treatment.