title: Implicit sequence learning in juvenile anorexia nervosa: neural mechanisms and the impact of starvation.
abstract: BACKGROUND
  Previous studies have reported that cognitive deficits occur in patients with anorexia nervosa (AN) and that these deficits may represent a predisposition towards developing AN or perpetuate the disorder. Specifically, dysfunctional implicit learning may contribute to the development of highly resistant dieting behaviours that are fundamental to the persistence of the disorder. Thus, the aims of this study were (a) to investigate implicit sequence learning in adolescent patients with AN before and after weight recovery and (b) to elucidate the associated neural mechanisms in acute AN relative to healthy controls.
  
  
  METHODS
  In a behavioural study, implicit sequence learning was assessed using a serial reaction time task in 27 adolescents with AN before (T1) and after weight recovery (T2) compared with age-matched healthy controls (HC) who were assessed at similar time intervals. The neural correlates of implicit sequence learning were subsequently investigated in 19 AN patients shortly after they were admitted to the hospital and 20 HC using functional magnetic resonance imaging (fMRI).
  
  
  RESULTS
  At T1, AN patients showed reduced sequence learning compared with HC. However, no behavioural differences between HC and AN patients were found at T2. At the neural level, acute AN patients showed reduced thalamic activation during sequence learning compared with HC subjects.
  
  
  CONCLUSIONS
  Our data suggest that the impaired implicit learning observed in adolescent AN patients before weight gain is a state-related dysfunction that normalises with weight gain. Thus, implicit learning deficits do not appear to represent a predisposition towards developing AN; rather, these deficits should be considered when planning psychotherapeutic interventions for acute AN. Reduced thalamic activation during the acute stage of AN may indicate a starvation-induced dysfunction of the neural circuitry that is involved in behavioural flexibility.
authors.affiliation: Department of Child and Adolescent Psychiatry, University Hospital RWTH Aachen, Aachen, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Firk
authors.affiliation: Department of Child and Adolescent Psychiatry, University Hospital RWTH Aachen, Aachen, Germany.
authors.forename: Verena
authors.initials: V
authors.lastname: Mainz
authors.affiliation: Department of Child and Adolescent Psychiatry, University Hospital RWTH Aachen, Aachen, Germany.|Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, Juelich, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Schulte-Ruether
authors.affiliation: Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, Juelich, Germany.|Department of Neurology, University Hospital Cologne, Cologne, Germany.
authors.forename: Gereon
authors.initials: G
authors.lastname: Fink
authors.affiliation: Department of Child and Adolescent Psychiatry, University Hospital RWTH Aachen, Aachen, Germany.
authors.forename: Beate
authors.initials: B
authors.lastname: Herpertz-Dahlmann
authors.affiliation: Department of Child and Adolescent Psychiatry, University Hospital RWTH Aachen, Aachen, Germany.|Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, Juelich, Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Konrad
mesh_terms: D000293:Adolescent; D000856:Anorexia Nervosa / Q000503:physiopathology*; D002648:Child; D005260:Female; D006801:Humans; D007858:Learning / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D013788:Thalamus / Q000503:physiopathology*; D015430:Weight Gain / Q000502:physiology*
keywords: Anorexia nervosa; functional magnetic resonance imaging; implicit sequence learning; serial reaction time task