ERIC Number: EJ793235
Record Type: Journal
Publication Date: 2008-May
Pages: 12
Abstractor: Author
ISBN: N/A
ISSN: ISSN-0006-8950
EISSN: N/A
Differential Effects of Insular and Ventromedial Prefrontal Cortex Lesions on Risky Decision-Making
Clark, L.; Bechara, A.; Damasio, H.; Aitken, M. R. F.; Sahakian, B. J.; Robbins, T. W.
Brain, v131 n5 p1311-1322 May 2008
The ventromedial prefrontal cortex (vmPFC) and insular cortex are implicated in distributed neural circuitry that supports emotional decision-making. Previous studies of patients with vmPFC lesions have focused primarily on decision-making under uncertainty, when outcome probabilities are ambiguous (e.g. the Iowa Gambling Task). It remains unclear whether vmPFC is also necessary for decision-making under risk, when outcome probabilities are explicit. It is not known whether the effect of insular damage is analogous to the effect of vmPFC damage, or whether these regions contribute differentially to choice behaviour. Four groups of participants were compared on the Cambridge Gamble Task, a well-characterized measure of risky decision-making where outcome probabilities are presented explicitly, thus minimizing additional learning and working memory demands. Patients with focal, stable lesions to the vmPFC (n = 20) and the insular cortex (n = 13) were compared against healthy subjects (n = 41) and a group of lesion controls (n = 12) with damage predominantly affecting the dorsal and lateral frontal cortex. The vmPFC and insular cortex patients showed selective and distinctive disruptions of betting behaviour. VmPFC damage was associated with increased betting regardless of the odds of winning, consistent with a role of vmPFC in biasing healthy individuals towards conservative options under risk. In contrast, patients with insular cortex lesions failed to adjust their bets by the odds of winning, consistent with a role of the insular cortex in signalling the probability of aversive outcomes. The insular group attained a lower point score on the task and experienced more "bankruptcies". There were no group differences in probability judgement. These data confirm the necessary role of the vmPFC and insular regions in decision-making under risk. Poor decision-making in clinical populations can arise via multiple routes, with functionally dissociable effects of vmPFC and insular cortex damage. (Contains 6 figures and 2 tables.)
Descriptors: Patients, Memory, Brain Hemisphere Functions, Probability, Neurological Impairments, Risk, Decision Making, Task Analysis, Comparative Analysis, Behavior Patterns, Scores
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Publication Type: Journal Articles; Reports - Research
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A
Grant or Contract Numbers: N/A