title: Patients with obsessive-compulsive disorder are impaired in associative learning based on external feedback.
abstract: BACKGROUND
  Patients with obsessive-compulsive disorder (OCD) have to repeat their actions before feeling satisfied that the action reached its intended goal. Learning theory predicts that this may be due to a failure in the processing of external feedback.
  
  
  METHODS
  We examined the performance of 29 OCD patients and 28 healthy volunteers on an associative learning task, in which initial learning is based solely on external feedback signals. Feedback valence was manipulated with monetary gains and losses.
  
  
  RESULTS
  As predicted, OCD patients were impaired during initial, external feedback-driven learning but not during later learning stages. The emotional salience of the feedback modulated learning during the initial stage in patients and controls alike. During later learning stages, however, patients approached near-normal performance with rewarding feedback but continued to produce deficient learning with punishing feedback.
  
  
  CONCLUSIONS
  OCD patients have a fundamental impairment in updating behavior based on the external outcome of their actions, possibly mediated by faulty error signals in response selection processes.
authors.affiliation: Institute for Clinical and Experimental Neurosciences, Department of Psychiatry, VU University Medical Center Amsterdam, Amsterdam, The Netherlands.
authors.forename: M M
authors.initials: MM
authors.lastname: Nielen
authors.forename: J A
authors.initials: JA
authors.lastname: den Boer
authors.forename: H G O M
authors.initials: HG
authors.lastname: Smid
mesh_terms: D000328:Adult; D001245:Association Learning; D001288:Attention; D002755:Choice Behavior; D030141:Feedback, Psychological; D005260:Female; D006801:Humans; D008297:Male; D009771:Obsessive-Compulsive Disorder / Q000175:diagnosis* / Q000523:psychology; D010364:Pattern Recognition, Visual; D010555:Personality Inventory / Q000706:statistics & numerical data; D011594:Psychometrics; D011597:Psychomotor Performance; D011678:Punishment; D012201:Reward; D013223:Statistics as Topic; D055815:Young Adult