title: Deep brain stimulation of the subthalamic nucleus selectively improves learning of weakly associated cue combinations during probabilistic classification learning in Parkinson's disease.
abstract: OBJECTIVE
  Evidence from functional imaging and clinical studies on patients with Parkinson's disease (PD) or Huntington's disease (HD) suggests that the basal ganglia play a crucial role in learning on the weather prediction task (WPT). Using deep brain stimulation (DBS) on versus off methodology, the aim of this study was to investigate the effect of altering the output from the basal ganglia to the prefrontal cortex on implicit probabilistic classification learning on the WPT by patients with PD.
  
  
  METHODS
  Eleven PD patients with bilateral DBS of the subthalamic nucleus (STN) and 13 matched controls completed 200 trials of the WPT on 2 separate occasions, with the patients tested with DBS of the STN on or off.
  
  
  RESULTS
  DBS of the STN had no effect on overall WPT learning. However, STN DBS selectively improved implicit learning of cue combinations that were weakly (implicitly), rather than strongly (explicitly), associated with the WPT outcome.
  
  
  CONCLUSIONS
  Results suggest that the STN plays a role in implicit probabilistic classification learning by altering basal ganglia output to the frontal cortex.
authors.affiliation: Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, England.
authors.forename: Leonora
authors.initials: L
authors.lastname: Wilkinson
authors.forename: Mazda
authors.initials: M
authors.lastname: Beigi
authors.forename: David A
authors.initials: DA
authors.lastname: Lagnado
authors.forename: Marjan
authors.initials: M
authors.lastname: Jahanshahi
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D002755:Choice Behavior; D003463:Cues; D046690:Deep Brain Stimulation / Q000379:methods; D005260:Female; D006801:Humans; D007858:Learning; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000523:psychology* / Q000628:therapy*; D020531:Subthalamic Nucleus / Q000503:physiopathology*