title: Frontopolar cortical inefficiency may underpin reward and working memory dysfunction in bipolar disorder.
abstract: OBJECTIVE
  Emotional dysregulation in bipolar disorder is thought to arise from dysfunction within prefrontal cortical regions involved in cognitive control coupled with increased or aberrant activation within regions engaged in emotional processing. The aim of this study was to determine the common and distinct patterns of functional brain abnormalities during reward and working memory processing in patients with bipolar disorder.
  
  
  METHODS
  Participants were 36 euthymic bipolar disorder patients and 37 healthy comparison subjects matched for age, sex and IQ. Functional magnetic resonance imaging (fMRI) was conducted during the Iowa Gambling Task (IGT) and the n-back working memory task.
  
  
  RESULTS
  During both tasks, patients with bipolar disorder demonstrated a pattern of inefficient engagement within the ventral frontopolar prefrontal cortex with evidence of segregation along the medial-lateral dimension for reward and working memory processing, respectively. Moreover, patients also showed greater activation in the anterior cingulate cortex during the Iowa Gambling Task and in the insula during the n-back task.
  
  
  CONCLUSIONS
  Our data implicate ventral frontopolar dysfunction as a core abnormality underpinning bipolar disorder and confirm that overactivation in regions involved in emotional arousal is present even in tasks that do not typically engage emotional systems.
authors.affiliation: Section of Neurobiology of Psychosis, Department of Psychosis Studies, Kings College London, London, UK. jigar.jogia@kcl.ac.uk
authors.forename: Jigar
authors.initials: J
authors.lastname: Jogia
authors.forename: Danai
authors.initials: D
authors.lastname: Dima
authors.forename: Veena
authors.initials: V
authors.lastname: Kumari
authors.forename: Sophia
authors.initials: S
authors.lastname: Frangou
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000503:physiopathology*; D002540:Cerebral Cortex / Q000503:physiopathology*; D005260:Female; D006179:Gyrus Cinguli / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008569:Memory Disorders / Q000503:physiopathology*; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D017397:Prefrontal Cortex / Q000503:physiopathology*; D012201:Reward