Evaluation Summary:
This manuscript examines how effort is integrated into economic decisions by recording neural activity from the dorsal anterior cingulate cortex (ACC) in monkeys, while requiring animals to choose between different juice types offered in variable amounts and with different action costs. The ACC is a relevant area because some theories have suggested it is important for evaluating or selecting among potential actions during decision-making, although evidence supporting this idea has been inconsistent. The main results provide evidence against the notion that ACC contributes to evaluation of potential actions. Instead, neurons predominantly coded for post-decision variables, such as cost of the chosen target and the juice type of the chosen offer, but not pre-decision variables, such as offer values. This is in contrast to OFC encoding in the same task (and same subjects), in which neurons encoded the effort associated with choice options. The authors conclude that ACC is unique in representing more post-decision variables than OFC, and in its encoding of outcomes in several reference frames (chosen juice, chosen cost, and chosen action). Together, the results are convincing and highlight potentially unique roles of ACC neurons in learning and decision making.
(This preprint has been reviewed by eLife. We include the public reviews from the reviewers here; the authors also receive private feedback with suggested changes to the manuscript. Reviewer #2 agreed to share their name with the authors.)