title: Reduced brain reward response during cooperation in first-degree relatives of patients with psychosis: an fMRI study.
abstract: BACKGROUND
  Psychosis is characterized by a profound lack of trust and disturbed social interactions. Investigating the neural basis of these deficits is difficult because of medication effects but first-degree relatives show qualitatively similar abnormalities to patients with psychosis on various tasks. This study aimed to investigate neural activation in siblings of patients in response to an interactive task. We hypothesized that, compared to controls, siblings would show (i) less basic trust at the beginning of the task and (ii) reduced activation of the brain reward and mentalizing systems.
  
  
  METHODS
  Functional magnetic resonance imaging (fMRI) data were acquired on 50 healthy siblings of patients with psychosis and 33 healthy controls during a multi-round trust game with a cooperative counterpart. An a priori region-of-interest (ROI) analysis of the caudate, temporoparietal junction (TPJ), superior temporal sulcus (STS), insula and medial prefrontal cortex (mPFC) was performed focusing on the investment and repayment phases. An exploratory whole-brain analysis was run to test for group-wise differences outside these ROIs.
  
  
  RESULTS
  The siblings' behaviour during the trust game did not differ significantly from that of the controls. At the neural level, siblings showed reduced activation of the right caudate during investments, and the left insula during repayments. In addition, the whole-brain analysis revealed reduced putamen activation in siblings during investments.
  
  
  CONCLUSIONS
  The findings suggest that siblings show aberrant functioning of regions traditionally involved in reward processing in response to cooperation, which may be associated with the social reward deficits observed in psychosis.
authors: Department of Educational Neuroscience, Faculty of Psychology and Education,VU University Amsterdam,The Netherlands.
authors: P M
authors: PM
authors: Gromann
authors: CSI Laboratory, Department of Psychosis Studies, Institute of Psychiatry,King's College London,UK.
authors: S S
authors: SS
authors: Shergill
authors: Department of Early Psychosis, AMC, Academic Psychiatric Centre, Amsterdam,The Netherlands.
authors: L
authors: L
authors: de Haan
authors: Department of Educational Neuroscience, Faculty of Psychology and Education,VU University Amsterdam,The Netherlands.
authors: D G J
authors: DG
authors: Meewis
authors: Department of Educational Neuroscience, Faculty of Psychology and Education,VU University Amsterdam,The Netherlands.
authors: A-K J
authors: AK
authors: Fett
authors: Department of Early Psychosis, AMC, Academic Psychiatric Centre, Amsterdam,The Netherlands.
authors: N
authors: N
authors: Korver-Nieberg
authors: Department of Educational Neuroscience, Faculty of Psychology and Education,VU University Amsterdam,The Netherlands.
authors: L
authors: L
authors: Krabbendam
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping / Q000379:methods; D003299:Cooperative Behavior; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011618:Psychotic Disorders / Q000503:physiopathology* / Q000523:psychology; D012201:Reward; D035781:Siblings / Q000523:psychology*; D013647:Task Performance and Analysis; D035502:Trust / Q000523:psychology; D055815:Young Adult