A mechanistic understanding of disrupted behaviour is crucial for developing treatments of neuropsychiatric syndromes in Parkinson’s disease (PD).

From an amoeba following a chemical gradient to higher concentrations of food to a PhD student struggling to write a coherent discussion for their thesis, all animal behaviour is ultimately governed by the rewarding outcomes it may lead to. It is no surprise then that dysfunction of systems crucial for reward processing in the brain has been implicated in a number of behavioural disturbances that occur in the context of neurological and psychiatric diseases. What is perhaps more surprising, however, is just how far we still have to go to understand how the complex interplay between functional neural networks, neuromodulators and the environment translates into normal reward-guided behaviour and, more importantly from our patients’ point of view, how …