title: Disorientation, confabulation, and extinction capacity: clues on how the brain creates reality.
abstract: BACKGROUND
  Disorientation and confabulation often have a common course, independent of amnesia. Behaviorally spontaneous confabulation is the form in which patients act according to a false concept of reality; they fail to abandon action plans (anticipations) that do not pertain to the present situation. This continued enactment of previously valid but meanwhile invalidated anticipations can be conceived as deficient extinction capacity, that is, failure to integrate negative prediction errors into behavior. In this study, we explored whether disorientation and behaviorally spontaneous confabulation are associated with extinction failure.
  
  
  METHODS
  Twenty-five patients hospitalized for neurorehabilitation after first-ever brain injury who either had severe amnesia (n = 17), an orbitofrontal lesion (n = 14), or both (n = 6) were tested regarding disorientation (questionnaire) and performed an experimental task of association learning and extinction. Five patients were also classified as behaviorally spontaneous confabulators.
  
  
  RESULTS
  Extinction capacity explained 66% of the variance of orientation in the whole group of patients (amnesics only, 56%; orbitofrontal group only, 90%), whereas association learning explained only 17% of the variance in the whole group (amnesics only, 7%; orbitofrontal group only, 16%). Also, extinction capacity, but not association learning, significantly distinguished between behaviorally spontaneous confabulators and all other subjects.
  
  
  CONCLUSIONS
  Disorientation and behaviorally spontaneous confabulation are strongly and specifically associated with a failure of extinction, the ability to learn that previously appropriate anticipations no longer apply. Rather than invoking high-level monitoring processes, the human brain seems to make use of an ancient biological faculty-extinction-to keep thought and behavior in phase with reality.
authors.affiliation: Division of Neurorehabilitation, Department of Clinical Neurosciences, University Hospital and University of Geneva, CH-1211 Geneva 14, Switzerland.
authors.forename: Louis
authors.initials: L
authors.lastname: Nahum
authors.forename: Radek
authors.initials: R
authors.lastname: Ptak
authors.forename: Béatrice
authors.initials: B
authors.lastname: Leemann
authors.forename: Armin
authors.initials: A
authors.lastname: Schnider
mesh_terms: D000328:Adult; D000368:Aged; D001930:Brain Injuries / Q000150:complications* / Q000523:psychology*; D003221:Confusion / Q000209:etiology*; D005108:Extinction, Psychological / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000209:etiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D009949:Orientation / Q000502:physiology; D010775:Photic Stimulation / Q000379:methods; D011936:Reality Testing; D021641:Recognition, Psychology / Q000502:physiology; D013223:Statistics as Topic; D018709:Statistics, Nonparametric; D014706:Verbal Learning / Q000502:physiology; D055815:Young Adult