Shame and embarrassment are two self-conscious emotions frequently experienced by Parkinson's disease (PD) patients. Shame and embarrassment scores strongly correlate with patient's quality of life, anxiety and depression ratings. However, the neurobiology of shame and embarrassment in PD and the influence of dopaminergic replacement therapy (DRT) is poorly understood.

The aim of this study is to characterize how brain structures and neuronal networks involved in Parkinson's disease-related shame, non-Parkinson's disease related shame and neutral control scenarios, are modulated by dopaminergic replacement therapy. For this purpose, functional MRI and connectivity measures between the basal ganglia and shame-related network will be analyzed while PD patients will perform a shame-induction task during both ON- (i.e. during the effect of DRT) and OFF-DRT (i.e. during the withdrawal of DRT) conditions. Correlation with clinical measures will be made.

Inclusion Criteria:

• Diagnosis of Parkinson's disease (PD) based on United Kingdom Parkinson's Disease Society Brain Bank Criteria

• Patients in the PD phase called "motor and non-motor fluctuations stage".

• Presence of motor and non-motor fluctuations are based on:

  1. For motor fluctuations: a score of 1 on item 4.1 and/or 1 on item 4.3 of the Movement Disorder Society Unified Parkinson's Disease Rating Scale IV
  2. For non-motor fluctuations: a score of 2 on item III of the Behavioral Assessment of Parkinson's Disease

• To be on dopaminergic replacement therapy.

Healthy controls:

subjects without any known central nervous system (CNS) lesion or CNS clinical signs on examination

Exclusion Criteria:

• Age greater than 80 years
• Dementia or mild cognitive impairment based on a score <26 on the MOCA
• Ongoing depression with suicidal ideation
• Any clinically meaningful non-stable renal, hepatic, cardiovascular, respiratory cerebrovascular disease or other serious progressive physical diseases
• Participating in a pharmacological study
• Any MRI contraindications
• Intolerable "OFF" states when the effects of the PD medication wear off (e.g., severe pain, anxiety, depression at the end of the dose or in the morning upon waking)
• Inability to provide informed consent (legal guardianship)
• Inability to speak or read French.

PD patients will be recruited from the outpatient movement disorder clinic of the Neurology Department at the Geneva University Hospital (HUG). Patients, who participated in previous studies and who are now followed up by private physicians, could also be contacted by trained members of the clinic/research staff to propose the study.

Flyers with a brief explanation of the project could also be distributed to the physicians to invite patients to consider participating and reach out to a staff member for further information.

Healthy controls will be recruited among the patients' spouses and through advertisement placed in the HUG and the University Medical Centre.