Organizing Principles of the Neural Circuits for Social Interaction

1 PROJECT SUMMARY 2 Cooperation and reciprocation are a hallmark of human behavior and key for creating and maintaining 3 social bonds. Yet despite their importance to both normal and abnormal social function, little is known 4 regarding their single neuronal and population underpinnings. 5 We propose to study, for the first time, how representations of recent social experience are formed 6 and maintained, then retrieved and updated with the goal of elucidating how these ultimately guide social 7 cooperative behavior. We will quantify cooperation using rhesus macaques playing the well-studied 8 iterated Prisoner’s dilemma game (iPD). In iPD, players can repeatedly cooperate for the common good 9 or exploit the other for their own benefit, and change their choices based on the other’s preceding move. 10 Using this approach, we previously described a neuronal circuit in the dorsal Anterior Cingulate Cortex 11 (dACC) where subsets of neural populations encode cooperative decisions and expected reward of other 12 individuals, distinct from neurons encoding one’s own decisions and reward. 13 Here, we build on these findings to investigate how the brain integrates recent interactions to support 14 cooperation. We will use large-scale simultaneous recordings in the primate Prefrontal Cortex to study 15 representations of one’s own and others’ actions, to delineate the functional neural architecture that 16 allow dynamic responses in ever-changing social contexts, and to study inter-brain neural synchrony 17 between monkeys cooperating while playing iPD. Such understanding is crucial for parsing how social 18 behavior falls apart in an array of neurological and psychiatric disorders and for devising future targeted 19 treatment of debilitating social disorders.