title: HIV infection results in ventral-striatal reward system hypo-activation during cue processing.
abstract: OBJECTIVE
  Functional MRI has thus far demonstrated that HIV has an impact on frontal-striatal systems involved in executive functioning. The potential impact of HIV on frontal-striatal systems involved in reward processing has yet to be examined by functional MRI. This study therefore aims to investigate the effects of HIV infection on reward processing by examining the function of the ventral-striatal reward system during a monetary incentive delay task.
  
  
  METHODS
  This is a cross-sectional case-control study.
  
  
  METHODS
  Eighteen combined antiretroviral therapy-naive HIV-positive (HIV+) participants, as well as 16 matched healthy controls, performed a monetary incentive delay task. This paradigm assesses behaviour as well as functional brain activity-associated reward anticipation and reward outcome.
  
  
  RESULTS
  HIV+ participants showed a general decrease in activation associated with both neutral as well as potentially rewarding cues in their ventral striatum. We found normal activity related to reward outcome in the orbito-frontal cortex. Despite HIV+ participants' reaction times being significantly slower when independently measured from the reward paradigm, this performance deficit normalized during the performance of the reward task.
  
  
  CONCLUSIONS
  HIV caused a decrease in activity during cue processing in the ventral striatum, with normal cortical functioning during reward outcome processing. Our results therefore suggest that HIV not only has an impact on fronto-striatal systems involved in executive functioning, but also has a direct impact on the function of the ventral-striatal reward system.
authors.affiliation: aDepartment of Psychiatry, University of Stellenbosch, Cape Town, South Africa bBrain Center Rudolf Magnus, University of Utrecht, Utrecht, The Netherlands cInstitute for Virology and Immunobiology, University of Würzburg, Würzburg, Germany dMedical Research Council (Unit on Anxiety and Stress Disorders), SU/UCT eDepartment of Psychiatry, University of Cape Town fDepartment of Radiology, Stellenbosch University, University of Stellenbosch, Cape Town, South Africa.
authors.forename: Stéfan du
authors.initials: Sd
authors.lastname: Plessis
authors.forename: Matthijs
authors.initials: M
authors.lastname: Vink
authors.forename: John A
authors.initials: JA
authors.lastname: Joska
authors.forename: Eleni
authors.initials: E
authors.lastname: Koutsilieri
authors.forename: Asif
authors.initials: A
authors.lastname: Bagadia
authors.forename: Dan J
authors.initials: DJ
authors.lastname: Stein
authors.forename: Robin
authors.initials: R
authors.lastname: Emsley
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology*; D006679:HIV Seropositivity / Q000503:physiopathology* / Q000523:psychology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests; D011930:Reaction Time; D012044:Regression Analysis; D066328:Ventral Striatum / Q000503:physiopathology*; D055815:Young Adult