Reward learning deficits in Parkinson’s disease depend on depression

Abstract

BackgroundDepression is one of the most common and debilitating non-motor symptoms of Parkinsons disease (PD). The neurocognitive mechanisms underlying depression in PD are unclear and treatment is often suboptimal.\n\nMethodsWe investigated the role of striatal dopamine in reversal learning from reward and punishment by combining a controlled medication withdrawal procedure with functional magnetic resonance imaging (fMRI) in 22 non-depressed PD patients and 19 PD patients with past or present PD-related depression.\n\nResultsPD patients with a PD-related depression (history) exhibited impaired reward versus punishment reversal learning as well as reduced reward versus punishment-related BOLD signal in the striatum (putamen) compared with non-depressed PD patients. No effects of dopaminergic medication were observed.\n\nConclusionsThe present findings demonstrate that impairments in reversal learning from reward versus punishment and associated reward-related striatal signalling depend on the presence of (a history of) depression in PD.