Brain Mechanisms of Social Perception in Parkinson's Disease

Inclusion Criteria: * Male or female between 30 and 75 years of age * Freely-given informed consent to participate to this study (written form) * Affiliated with a social security system or equivalent; * Person diagnosed with Parkinson's disease according to MDS-UPDRS criteria for at least 3 years and receiving dopaminergic treatment (e.g. : LEVODOPA, CARBIDOPA, BENZERASIDE, ENTACAPONE, MODOPAR, SINEMET, STALEVO, PRAMIPEXOLE, SIFROL, ROPINIROLE, REQUIP ; ROTIGOTINE, NEUPRO, PIRIBEDIL, TRIVASTAL, RASAGILINE, AZILECT, CONTAM, AMANTADINE, MANTADIX, APOMORPHINE, APOKINON, DOPACEPTIN, FOSLEVODOPA, FOSCARBIDOPA, SCYOVA) (for patients only) * Effective contraception for women of childbearing age or post-menopausal women (only for patients and healthy volunteers in stage 2 "imaging") * Requiring dopa testing as part of routine care (only for patients in stage 2 "imaging") * No disabling cognitive impairment (MOCA score ≥ 26) * No diagnosis of chronic disease associated with disability (only for healthy volunteers) Exclusion Criteria: * Contraindication to MRI (only for patients and healthy volunteers in step 2 "imaging"): * Wearing a pacemaker not approved for 3 Tesla MRI * Presence of intracerebral ferromagnetic or magnetizable material * Presence of intraocular ferromagnetic or magnetizable foreign bodies * Presence of non-removable ferro-magnetic or magnetizable foreign bodies in the cephalic region * Claustrophobia * History of head trauma with loss of consciousness lasting more than 30 min (only for patients and healthy volunteers in step 2 "imaging") * Participant not agreeing to be informed in the event of incidental discovery of an abnormality on MRI (only for patients and healthy volunteers in stage 2 "imaging") * Tremor or disabling dyskinesias preventing MRI (only for patients in stage 2) * Having exceeded the annual amount of compensation allowed for participation in research protocols (only for healthy volunteers) * Pregnant, parturient or breast-feeding women * Persons deprived of liberty by judicial or administrative decision * Persons under psychiatric care * Persons admitted to a health or social institution for purposes other than research * Adults under legal protection (guardianship, curatorship) * Participants in other intervention research involving a period of exclusion still in progress at the time of pre-inclusion.