Subthalamic Nucleus Stimulation Impairs Motivation: Implication for Apathy in Parkinson's Disease.

Taken together, these data provide experimental evidence that chronic subthalamic nucleus deep brain stimulation by itself can induce loss of motivation, reminiscent of apathy, independently of the dopaminergic neurodegenerative process or reduction in dopamine replacement therapy, presumably reflecting a dopaminergic-driven deficit. Therefore, our data help to clarify and reconcile conflicting clinical observations by highlighting some of the mechanisms of the neuropsychiatric side effects induced by chronic subthalamic nucleus deep brain stimulation. © 2020 International Parkinson and Movement Disorder Society.