Neural activity in macaque medial frontal cortex represents others' choices

Predicting the behavior of others is a fundamental skill in primate social life. We tested the role of medial frontal cortex in the prediction of other agents' behavior in two male macaques, using a monkey-human interactive task in which their actor-observer roles were intermixed. In every trial, the observer monitored the actor's choice to reject it for a different one when he became the actor on the subsequent trial. In the delay period preceding the action, we identified neurons modulated by the agent's identity, as well as a group of neurons encoding the agent's future choice, some of which were neurons that showed differential patterns of activity between agents. The ability of these neurons to flexibly move from 'self-oriented' to 'other-oriented' representations could correspond to the "other side of the coin" of the simulative mirroring activity. Neurons that changed coding scheme, together with neurons exclusively involved in the prediction of the other agent's choice, show a neural substrate for predicting or anticipating others' choices beyond simulation.