title: In Parkinson's disease STN stimulation enhances responsiveness of movement initiation speed to high reward value.
abstract: The subthalamic nucleus (STN) is part of the motor, associative, and limbic cortico-striatal circuits through which it can influence a range of behaviours, with preclinical and clinical evidence suggesting that the STN is involved in motivational modulation of behaviour. In the present study, we investigated if in Parkinson's disease (PD) motivational modulation of movement speed is altered by deep brain stimulation (DBS) of the STN (STN-DBS).
  
  
  
  We studied the effect of monetary incentive on speed of movement initiation and execution in a computer-based simple reaction time task in 10 operated patients with Parkinson's disease using a STN DBS ON/OFF design and also in 11 healthy participants.
  
  
  
  Prospect of reward improved speed of movement initiation in PD patients both with STN-DBS ON and OFF. However, only with STN-DBS ON, the patients showed greater speeding of initiation time with higher reward magnitude, suggesting enhanced responsivity to higher reward value. Also, on the rewarded trials, PD patients ON stimulation made more anticipation errors than on unrewarded trials, reflecting a propensity to impulsive responses triggered by prospect of reward by subthalamic stimulation. The motivational modulation of movement speed was preserved and enhanced in PD with STN-DBS.
  
  
  
  Motivational modulation of movement speed in PD is maintained with STN-DBS, with STN stimulation having a further energizing effect on movement initiation in response to greater incentive value. Our results suggest that STN plays a role in integrating motivational influences into motor action, which may explain some previous reports of STN-DBS induced impulsivity with increased motivational salience of stimuli.
authors.affiliation: Department of Neurology, University Medical Centre Ljubljana, Zaloska 2, 1000 Ljubljana, Slovenia; Sobell Department of Motor Neuroscience & Movement Disorders, UCL, Institute of Neurology, 33 Queen Square, London, WC1N 3BG, United Kingdom.
authors.forename: Maja
authors.initials: M
authors.lastname: Kojovic
authors.affiliation: Sobell Department of Motor Neuroscience & Movement Disorders, UCL, Institute of Neurology, 33 Queen Square, London, WC1N 3BG, United Kingdom; Department of Clinical Psychology, Trinity College Dublin, University of Dublin, Dublin 2, Ireland; Department of Clinical Psychology, University College Dublin, Stillorgan Rd, Belfield, Dublin 4, Ireland.
authors.forename: Andrea
authors.initials: A
authors.lastname: Higgins
authors.affiliation: Sobell Department of Motor Neuroscience & Movement Disorders, UCL, Institute of Neurology, 33 Queen Square, London, WC1N 3BG, United Kingdom. Electronic address: m.jahanshahi@ucl.ac.uk.
authors.forename: Marjan
authors.initials: M
authors.lastname: Jahanshahi
mesh_terms: D000328:Adult; D000368:Aged; D046690:Deep Brain Stimulation / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008609:Mental Status Schedule; D008875:Middle Aged; D009042:Motivation / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D010300:Parkinson Disease / Q000503:physiopathology / Q000523:psychology / Q000628:therapy*; D011930:Reaction Time / Q000502:physiology; D012201:Reward; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D020531:Subthalamic Nucleus / Q000502:physiology; D013997:Time Factors; D016896:Treatment Outcome
keywords: Deep brain stimulation; Motivation; Parkinson’s disease; Reaction times; Reward; Subthalamic nucleus