Impulsive and compulsive behaviors occur in up to 46% of Parkinson's Disease (PD) patients
taking dopamine agonist (DAA) medications. While these abnormal social behaviors have been
studied in other neurodegenerative disorders, the true incidence of social problems, and the
relationship to dopamine therapy, in PD patients remains unknown. This study is aiming to
determine if dopamine agonists alter social decision-making and to determine if impaired
social decision-making relates to dopamine-induced mesolimbic network dysfunction in PD
patients. The protocol will include a screening visit, and on-DAA visit, and an off-DAA
visit. For both the on and off DAA visits, participants will continue taking
Carbidopa-Levodopa, but will withdrawal off of other PD related medications. Both visits will
include an MRI, fMRI shock task, questionnaires to be filled out by other the participant and
the caregiver, moral-decision making computer tasks, and the Unified Parkinsons Disease
Rating Scale (UPDRS) part II and III. For the on-DAA visit, participants will take
Pramipexole. For the off-DAA visit, participants will receive a placebo. Participants will
remind blinded to which medication they are receiving that day and will be counterbalanced
such that all participants will not take the Pramipexole or placebo on the same days.