title: Decision-making and trait impulsivity in bipolar disorder are associated with reduced prefrontal regulation of striatal reward valuation.
abstract: Bipolar disorder is characterized by impaired decision-making captured in impulsivity and risk-taking. We sought to determine whether this is driven by a failure to effectively weight the lower-order goal of obtaining a strongly desired reward in relation to higher-order goals, and how this relates to trait impulsivity and risk-taking. We hypothesized that in bipolar disorder the weighting of valuation signals converging on ventromedial prefrontal cortex are more heavily weighted towards ventral striatum inputs (lower-order), with less weighting of dorsolateral prefrontal cortex inputs (higher-order). Twenty euthymic patients with bipolar disorder not in receipt of antipsychotic medication and 20 case-matched controls performed a roulette task during functional magnetic resonance imaging. Activity in response to high-probability ('safe') and low-probability ('risky') prospects was measured during both anticipation, and outcome. In control subjects, anticipatory and outcome-locked activity in dorsolateral prefrontal cortex was greater for safe than risky reward prospects. The bipolar disorder group showed the opposite pattern with preferential response to risky rewards. This group also showed increased anticipatory and outcome-locked activity in ventral striatum in response to rewards. In control subjects, however, ventromedial prefrontal activation was positively associated with both ventral striatum and dorsolateral prefrontal activity; patients evidenced a strong positive association with ventral striatum, but a negative association with dorsolateral prefrontal cortex. Response to high-probability rewards in dorsolateral prefrontal cortex was inversely associated with trait impulsivity and risk-taking in the bipolar disorder group. Our findings suggest that clinically impulsive and risky decision-making are related to subjective valuation that is biased towards lower-order preference, with diminished integration of higher-order goals. The findings extend a functional neuroanatomical account of disorders characterized by clinically impulsive decision-making, and provide targets for evaluating interventions that foster self-control.
authors.affiliation: 1 School of Psychological Sciences, University of Manchester, Manchester M13 9PL, UK Liam.Mason@kcl.ac.uk.
authors.forename: Liam
authors.initials: L
authors.lastname: Mason
authors.affiliation: 2 Institute of Psychology, Health and Society, University of Liverpool, Liverpool L69 3BX, UK.
authors.forename: Noreen
authors.initials: N
authors.lastname: O'Sullivan
authors.affiliation: 1 School of Psychological Sciences, University of Manchester, Manchester M13 9PL, UK.
authors.forename: Daniela
authors.initials: D
authors.lastname: Montaldi
authors.affiliation: 2 Institute of Psychology, Health and Society, University of Liverpool, Liverpool L69 3BX, UK.
authors.forename: Richard P
authors.initials: RP
authors.lastname: Bentall
authors.affiliation: 1 School of Psychological Sciences, University of Manchester, Manchester M13 9PL, UK.
authors.forename: Wael
authors.initials: W
authors.lastname: El-Deredy
mesh_terms: D000328:Adult; D001479:Basal Ganglia / Q000503:physiopathology*; D001714:Bipolar Disorder / Q000503:physiopathology*; D016022:Case-Control Studies; D003657:Decision Making / Q000502:physiology; D059907:Functional Neuroimaging / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D007175:Impulsive Behavior / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests; D017397:Prefrontal Cortex / Q000503:physiopathology*; D011569:Psychiatric Status Rating Scales; D012201:Reward; D012309:Risk-Taking
keywords: accumbens; bipolar disorder; mania; reward; risk; striatum