Risk-sensitive decision-making in patients with posterior parietal and ventromedial prefrontal cortex injury.
Successful choice under risk requires the integration of information about outcome probabilities and values and implicates a brain network including the ventromedial prefrontal cortex (vmPFC) and posterior parietal cortex (pPAR). Damage to the vmPFC is linked to poor decision-making and increased risk-taking. Electrophysiological and neuroimaging data implicate the pPAR in the processing of reward probability during choice, but the causal contribution of this area has not been established. We compared patients with lesions to the pPAR (n = 13), vmPFC (n = 13), and healthy volunteers (n = 22) on the Roulette Betting Task, a measure of risk-sensitive decision-making. Both lesion groups were impaired in adjusting their bets to the probability of winning. This impairment was correlated with the extent of pPAR, but not vmPFC, damage. In addition, the vmPFC group chose higher bets than healthy controls overall, an effect that correlated with lesion volume in the medial orbitofrontal cortex. Both lesion groups earned fewer points than healthy controls. The groups did not differ on 2 tasks assessing probabilistic reasoning outside of a risk-reward context. Our results demonstrate the causal involvement of both the pPAR and vmPFC in risk-sensitive choice and indicate distinguishable roles of these areas in probability processing and risk appetite.
Department of Psychology Behavioural and Clinical Neuroscience Institute (BCNI), University of Cambridge, Cambridge, UK, Institute of Cognitive Neuroscience, University College London, London WC1N 3AR, UK.
Bettina
B
Studer
Institute of Cognitive Neurology (INECO), Favaloro University, Buenos Aires, Argentina and.
Facundo
F
Manes
Department of Experimental Psychology, University of Oxford, Oxford, UK.
Glyn
G
Humphreys
Department of Psychology Behavioural and Clinical Neuroscience Institute (BCNI), University of Cambridge, Cambridge, UK.
Trevor W
TW
Robbins
Department of Psychology Behavioural and Clinical Neuroscience Institute (BCNI), University of Cambridge, Cambridge, UK.
Luke
L
Clark
D000368:Aged; D002755:Choice Behavior / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010296:Parietal Lobe / Q000473:pathology / Q000503:physiopathology*; D017397:Prefrontal Cortex / Q000473:pathology / Q000503:physiopathology*; D012201:Reward; D012306:Risk; D012309:Risk-Taking
decision-making; lesion study; posterior parietal cortex; risk; ventromedial prefrontal cortex