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Description
Social interactions often unfold in real time with direct face-to-face visibility. Yet, the behavioural and neuronal mechanisms of dynamic strategic interactions remain not well understood. Here, we studied macaque monkeys in a dyadic Bach-or-Stravinsky (BoS) economic decision game, which incentivizes coordination but entails an inherent conflict about which of two options to coordinate on. Macaques made reach decisions before, simultaneously with, or after a predictable or unpredictable human confederate partner, a conspecific, or alone but with similar action timing. Under naturalistic conditions of mutual action visibility, macaques learned to monitor partner’s actions, either following an observed choice or anticipating predictable choices.
Most premotor cortex neurons were spatially selective in solo and dyadic contexts, but a subset of neurons encoded self-action only in the dyadic context, and action sequence primarily influenced activity in the presence of a partner. When monkeys acted first, population-level decoding reflected the predictable partner’s upcoming choice even before the partner’s action, with decoding accuracy further enhanced after the action. Coordination success could only be decoded after the second action (monkey's or partner's) became evident. This decoding was strongest for unpredictable and weakest for reward-irrelevant partners, indicating modulation by relevance. During passive observation – where monkeys received reward based on the partner’s choice but did not act – the representation of the partner’s spatial choice was weak, while the representation of expected value became stronger. These results show how premotor cortex emphasizes relevant task dimensions, integrating others’ actions with one’s own goals and choices during dynamic strategic coordination.
