Distinct neural mechanisms of risk and ambiguity: a meta-analysis of decision-making.

Converging evidence from human and animal studies suggests that decision-making relies upon a distributed neural network based in the frontal lobes. In particular, models of decision-making emphasize the involvement of orbitofrontal cortices (OFC) and the medial wall. While decision-making has been studied broadly as a class of executive function, recent models have suggested the differentiation between risky and ambiguous decision-making. Given recent emphasis on the role of OFC in affectively laden "hot" executive function and dorsolateral prefrontal cortex (DLPFC) in more purely cognitive "cool" executive function, we hypothesize that the neural substrates of decision-making may differ depending on the nature of the decision required. To test this hypothesis, we used recently developed meta-analytic techniques to examine the existent functional neuroimaging literature. An initial meta-analysis of decision-making, both risky and ambiguous, found significantly elevated probabilities of activation in frontal and parietal regions, thalamus, and caudate. Ambiguous decision-making was associated with activity in DLPFC, regions of dorsal and subcallosal anterior cingulate cortex (ACC), and parietal cortex. Risky decision-making was associated with activity in OFC, rostral portions of the ACC, and parietal cortex. Direct statistical comparisons revealed significant differences between risky and ambiguous decision-making in frontal regions, including OFC, DLPFC, and ACC, that were consistent with study hypotheses. These findings provide evidence for the dissociation of neural circuits underlying risky and ambiguous decision-making, reflecting differential involvement of affective "hot" and cognitive "cool" processes.