Conference on Cognitive Computational Neuroscience

People naturally engage in complex, dynamic, often competitive social interactions. To understand the neurobiology of these behaviors, we studied humans and monkeys playing a virtual soccer game featuring continuous interactions. Both species adopted similarly complex strategies. Kicker unpredictability, optimal timing, and goalie responsiveness jointly determined game outcome. We used Gaussian Process (GP) classification to decompose these continuous behaviors to a series of discrete decisions to switch movement direction at each moment. We recorded neuronal activity in macaque mid-superior temporal sulcus (mSTS), putative homolog of the human temporo-parietal junction (TPJ), a brain area engaged during strategic social interactions. Two populations of mSTS neurons, residing on the upper and lower bank of mSTS respectively, exhibited distinct activity patterns during as well as after gameplay. During gameplay, mSTS neurons tracked self and opponent switch probabilities to determine the next switch point. Post gameplay, mSTS neurons evaluated outcome to preselect strategy set for the next trial. Inactivating mSTS reduced kicker's unpredictability as well as goalie's responsiveness to kicker behavior. These findings indicate mSTS evaluates strategies to fit the current behavioral context, consistent with the function of human TPJ.