Clinical Research Directory

Inclusion Criteria: * Age ≥ 75 years with PD according to Movement Disorders Society criteria (2015). * Clinical diagnosis of Alzheimer's disease * Has been on stable antiparkinsonian treatment for less than 3 months. * Ability to understand the principle of the study as well as its risks. * Written consent to participate in the trial. * Have social insurance * Agree to comply with all safety procedures during the study and its duration. * Ability to understand and freely give consent * Patient affiliated to social security or entitled beneficiary * Autonomy preserved Exclusion criteria : * age \<75 years * refusal to sign consent * MOCA \<23 * Presence of major behavioural problems that do not allow MRI to be performed under optimal conditions * Subjects unable to receive informed information, unable to participate in the study as a whole * Subjects with a diagnosis of atypical parkinsonian syndrome (Lewy body disease, progressive supranuclear palsy, multisystem atrophy, cortico-basal degeneration, etc.). * A classic contraindication to an MRI examination: claustrophobia, presence of incompatible foreign material, * Subjects who have practised horse riding at a high level, animal phobias, wish to stop studying, etc. * No affiliation to a social security scheme * Antiparkinsonian treatment has not been stable for at least 3 months. * People under protective supervision (guardianship, curatorship) * People under family guardianship are also excluded, as are people for whom a mandate for future protection has been activated.