This study investigates the impact of placebo on reward learning in Parkinson's disease (PD) patients, using a placebo dopaminergic manipulation combined with functional magnetic resonance imaging (fMRI). The researchers found that the mere expectation of dopamine release enhances reward learning and modulates learning-related signals in the striatum and the ventromedial prefrontal cortex (vmPFC). These effects were specific to learning from rewards, as neither medication nor placebo affected learning to avoid monetary loss. The findings suggest that expectations can shape learning and affect behavior, providing a neurobiological mechanism for the placebo effect. The study also highlights the potential for combining psychological and pharmacological factors to enhance treatment outcomes, particularly in PD, where dopamine modulation plays a crucial role in motor and cognitive symptoms.This study investigates the impact of placebo on reward learning in Parkinson's disease (PD) patients, using a placebo dopaminergic manipulation combined with functional magnetic resonance imaging (fMRI). The researchers found that the mere expectation of dopamine release enhances reward learning and modulates learning-related signals in the striatum and the ventromedial prefrontal cortex (vmPFC). These effects were specific to learning from rewards, as neither medication nor placebo affected learning to avoid monetary loss. The findings suggest that expectations can shape learning and affect behavior, providing a neurobiological mechanism for the placebo effect. The study also highlights the potential for combining psychological and pharmacological factors to enhance treatment outcomes, particularly in PD, where dopamine modulation plays a crucial role in motor and cognitive symptoms.