Dose dependent dopaminergic modulation of reward-based learning in Parkinson's disease

► Dopamine plays a modulatory role in different processes of reward-based learning. ► The current study examined learning in Parkinson's patients ON and OFF dopaminergic medication. ► Learning which actions yield reward was impaired when PD patients were off their DA medication. ► However, DA medication did not affect outcome evaluation. ► Larger doses of medication lead to suboptimal performance.