Neural correlates of decision-making during a Bayesian choice task.

Many critical decisions require evaluation of accumulated previous information and/or newly acquired evidence. Although neural correlates of belief updating have been investigated, how these neural processes guide decisions involving Bayesian choice is less clear. Here, we used functional MRI to investigate neural activity during a Bayesian choice task involving two sources of information: base rate odds ('odds') and sample evidence ('evidence'). Thirty-seven healthy control individuals performed the Bayesian choice task in which they had to make probability judgements. Average functional MRI activity during the trials where choice was consistent with use of Odds, use of Evidence, and use of Both was compared. Decision-making consistent with odds, evidence and both each strongly activated the bilateral executive network encompassing the bilateral frontal, cingulate, posterior parietal and occipital cortices. The Evidence consistent, compared with Odds consistent, decisions showed greater activity in the bilateral middle and inferior frontal and right lateral occipital cortices. Decisions consistent with the use of Both strategies were associated with increased activity in the bilateral middle frontal and superior frontal cortices. These findings support the conclusion that both overlapping and distinct brain regions within the frontoparietal network underlie the incorporation of different types of information into a Bayesian decision.