title: Implication of reward alterations in the expression of negative symptoms in 22q11.2 deletion syndrome: a behavioural and DTI study.
abstract: BACKGROUND
  Alterations of the reward system have been proposed as one of the core mechanisms underlying the expression of negative symptoms in schizophrenia. Specifically, deficits in specific reward components and white matter (WM) integrity of the reward system have been highlighted. The putative link between negative symptoms and the hedonic experience, or structural connectivity of the reward system has never been examined in the 22q11.2 deletion syndrome (22q11DS), a condition with increased risk for psychosis.
  
  
  METHODS
  Anticipatory and consummatory dimensions of pleasure were assessed in participants with 22q11DS (N = 54) and healthy controls (N = 55). In patients with 22q11DS, the association between pleasure scores and positive or negative symptoms was investigated. Furthermore, WM integrity of the accumbofrontal tract was quantified using diffusion tensor imaging (DTI). Associations between DTI measures, pleasure dimensions and negative symptoms were examined.
  
  
  RESULTS
  Patients with 22q11DS showed reduced anticipatory and consummatory pleasure compared to controls. Furthermore, anticipatory pleasure scores were negatively correlated to negative and positive symptoms in 22q11DS. WM microstructural changes of the accumbofrontal tract in terms of increased fractional anisotropy and reduced radial anisotropy were also identified in patients. However, no significant correlation between the DTI measures and pleasure dimensions or psychotic symptoms was observed.
  
  
  CONCLUSIONS
  This study revealed that participants with 22q11DS differed in their experience of pleasure compared to controls. The anticipatory pleasure component appears to be related to negative and positive symptom severity in patients. Alterations of WM integrity of the accumbofrontal tract seem to be related to myelination abnormalities in 22q11DS patients.
authors.affiliation: Department of Psychiatry,Office Médico-Pédagogique Research Unit, School of Medicine, University of Geneva,Geneva,Switzerland.
authors.forename: L
authors.initials: L
authors.lastname: Dubourg
authors.affiliation: Department of Psychiatry,Office Médico-Pédagogique Research Unit, School of Medicine, University of Geneva,Geneva,Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Schneider
authors.affiliation: Department of Psychiatry,Office Médico-Pédagogique Research Unit, School of Medicine, University of Geneva,Geneva,Switzerland.
authors.forename: M C
authors.initials: MC
authors.lastname: Padula
authors.affiliation: Department of Psychiatry,Office Médico-Pédagogique Research Unit, School of Medicine, University of Geneva,Geneva,Switzerland.
authors.forename: L
authors.initials: L
authors.lastname: Chambaz
authors.affiliation: Department of Psychiatry,Office Médico-Pédagogique Research Unit, School of Medicine, University of Geneva,Geneva,Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Schaer
authors.affiliation: Department of Psychiatry,Office Médico-Pédagogique Research Unit, School of Medicine, University of Geneva,Geneva,Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: Eliez
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D004062:DiGeorge Syndrome / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D057181:Pleasure / Q000502:physiology*; D012201:Reward; D066127:White Matter / Q000000981:diagnostic imaging*; D055815:Young Adult
keywords: 22q11.2 deletion syndrome; negative symptoms; reward system; white matter