Abstract
Despite the obvious importance of subjective preferences for guiding decisions, their neural substrate has rarely been investigated. Both people and animals often demonstrate strong aversions or preferences for options with uncertain rewards, making risk preference an attractive model for probing neural mechanisms underlying subjective valuation and decision-making. Here we show that monkeys systematically preferred the risky target in a visual gambling task, in which they chose between two visual targets offering the same mean reward but differing in reward uncertainty. Neuronal activity in posterior cingulate cortex (CGp), a brain area linked to visuospatial orienting and reward processing, was enhanced by the illumination of risky targets in their response fields. On a trial-by-trial basis, CGp activation was better predicted by preferences for the risky target than by target reward value and was independent of arousal-linked changes in reaction time or saccade metrics. CGp activity thus reflects subjective bias for a particular visual target location, rather than the objective rewards associated with it. These data implicate subjective scaling of CGp activity in the decision processes guiding visual orienting.
NEI, Klingenstein Foundation, EJLB Foundation