title: Trial-by-Trial Adjustments of Cognitive Control Following Errors and Response Conflict are Altered in Pediatric Obsessive Compulsive Disorder.
abstract: BACKGROUND
  Impairments of cognitive control have been theorized to drive the repetitive thoughts and behaviors of obsessive compulsive disorder (OCD) from early in the course of illness. However, it remains unclear whether altered trial-by-trial adjustments of cognitive control characterize young patients. To test this hypothesis, we determined whether trial-by-trial adjustments of cognitive control are altered in children with OCD, relative to healthy controls.
  
  
  METHODS
  Forty-eight patients with pediatric OCD and 48 healthy youth performed the Multi-Source Interference Task. Two types of trial-by-trial adjustments of cognitive control were examined: post-error slowing (i.e., slower responses after errors than after correct trials) and post-conflict adaptation (i.e., faster responses in high-conflict incongruent trials that are preceded by other high-conflict incongruent trials, relative to low-conflict congruent trials).
  
  
  RESULTS
  While healthy youth exhibited both post-error slowing and post-conflict adaptation, patients with pediatric OCD failed to exhibit either of these effects. Further analyses revealed that patients with low symptom severity showed a reversal of the post-conflict adaptation effect, whereas patients with high symptom severity did not show any post-conflict adaptation.
  
  
  CONCLUSIONS
  Two types of trial-by-trial adjustments of cognitive control are altered in pediatric OCD. These abnormalities may serve as early markers of the illness.
authors.affiliation: Department of Psychiatry, Medical School, University of Michigan Ann Arbor, MI, USA.
authors.forename: Yanni
authors.initials: Y
authors.lastname: Liu
authors.forename: William J
authors.initials: WJ
authors.lastname: Gehring
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Weissman
authors.forename: Stephan F
authors.initials: SF
authors.lastname: Taylor
authors.forename: Kate Dimond
authors.initials: KD
authors.lastname: Fitzgerald