title: Greater striatal responses to medication in Parkinson׳s disease are associated with better task-switching but worse reward performance.
abstract: Dopaminergic medication in Parkinson's disease has been proposed to improve cognitive processing by modulating the severely depleted dorsal striatum, while impairing reward processing by modulating the relatively intact ventral striatum. However, there is no direct (neural) evidence for this hypothesis. Here we fill this gap by scanning Parkinson's disease patients (n=15) ON and relatively OFF their dopaminergic medication using functional magnetic resonance imaging. During scanning, patients performed a task that enabled the simultaneous measurement of task-switching and reward-related processing. Brain-behavior correlations revealed that medication-related increases (ON-OFF) in switch-related BOLD signal (switch-repeat) in the dorsomedial striatum were associated, on an individual basis, with improvements in task-switching (i.e. a decreased switch cost). Conversely, medication-related increases (ON-OFF) in reward-related BOLD signal (high-low) in the ventromedial striatum were associated, on an individual basis, with impairments in performance in anticipation of reward (i.e. an increased reward cost). Linear regression analyses demonstrated that the positive relationship between medication-related changes in BOLD and the reward cost was unique to the ventromedial striatum, whereas the negative relationship between medication-related changes in BOLD and the switch cost was not unique to the dorsomedial striatum. These findings extend the dopamine overdose hypothesis, according to which dopamine-induced changes in dorsal and ventral striatal processing lead to cognitive improvement and impairment respectively.
authors.affiliation: Radboud University Nijmegen, Donders Institute for Brain, Cognition and Behaviour, Centre for Cognitive Neuroimaging, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands. Electronic address: aarts.esther@gmail.com.
authors.forename: Esther
authors.initials: E
authors.lastname: Aarts
authors.affiliation: Radboud University Nijmegen, Donders Institute for Brain, Cognition and Behaviour, Centre for Cognitive Neuroimaging, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands.
authors.forename: Abraham A M
authors.initials: AA
authors.lastname: Nusselein
authors.affiliation: Radboud University Nijmegen, Donders Institute for Brain, Cognition and Behaviour, Centre for Cognitive Neuroimaging, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands.
authors.forename: Peter
authors.initials: P
authors.lastname: Smittenaar
authors.affiliation: Radboud University Nijmegen, Donders Institute for Brain, Cognition and Behaviour, Centre for Cognitive Neuroimaging, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands; Radboud University Nijmegen Medical Centre, Donders Institute for Brain, Cognition and Behaviour, Department of Neurology, Parkinson Centre Nijmegen (ParC), P.O. Box 9101, 6500 HB Nijmegen, The Netherlands.
authors.forename: Rick C
authors.initials: RC
authors.lastname: Helmich
authors.affiliation: Radboud University Nijmegen Medical Centre, Donders Institute for Brain, Cognition and Behaviour, Department of Neurology, Parkinson Centre Nijmegen (ParC), P.O. Box 9101, 6500 HB Nijmegen, The Netherlands.
authors.forename: Bastiaan R
authors.initials: BR
authors.lastname: Bloem
authors.affiliation: Radboud University Nijmegen, Donders Institute for Brain, Cognition and Behaviour, Centre for Cognitive Neuroimaging, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands; Radboud University Nijmegen Medical Centre, Donders Institute for Brain, Cognition and Behaviour, Department of Psychiatry, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands.
authors.forename: Roshan
authors.initials: R
authors.lastname: Cools
mesh_terms: D000978:Antiparkinson Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001245:Association Learning / Q000187:drug effects; D001288:Attention / Q000187:drug effects / Q000502:physiology*; D003342:Corpus Striatum / Q000098:blood supply / Q000187:drug effects*; D015259:Dopamine Agents / Q000494:pharmacology* / Q000627:therapeutic use; D004576:Electromyography; D005260:Female; D007839:Functional Laterality; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood; D010300:Parkinson Disease / Q000188:drug therapy / Q000473:pathology*; D011930:Reaction Time / Q000187:drug effects; D012201:Reward
chemical_list: D000978:Antiparkinson Agents; D015259:Dopamine Agents; D010100:Oxygen
keywords: Cognition; Dopamine; Parkinson׳s disease; Reward; Striatum; fMRI