As a social species, our behavior affects both individual and collective fitness. For example, by reciprocating an action. Furthermore, our ability to predict and make sense of other’s actions, or Theory of Mind, plays a fundamental role in our social interactions. Despite the importance of group behavior and theory of mind to individual fitness, the neuronal mechanisms underlying these cognitive processes remain elusive. To start addressing this gap, we designed a series of tasks in different species to explore some of the processes underlying social interactions while simultaneously recording single neuronal activity from the prefrontal cortex. In macaques, we devised a group task in which each of three monkeys seated around a turntable chose one of the other monkeys to receive a food reward. We discovered that monkeys tend to reciprocate, suggesting that they keep track of other’s prior choices and rewards. In humans, we studied neuronal activity in the PFC during the canonical false belief task, in which we asked subjects to reason about others’ perspective. We found a rich representation of social dynamics in the PFC across both species. In monkeys, distinct subpopulations of dmPFC neurons reflected both the actor and reward recipient’s identity in the current and previous trial. Moreover, decoding neuronal activity can predict the animal’s upcoming decisions, and manipulating neuronal activity using electrical stimulation can alter them. Finally, we identified single neurons in the human dmPFC that encode information about others’ beliefs, distinguish between self and other-beliefs, and predict whether these beliefs are true or false – collectively representing the first description of individual neurons encoding human theory of mind. These studies highlight the role of the PFC in a wide array of social behaviors. Our unique multi-species approach harnesses the distinct advantages of each animal model to interrogate aspects of prefrontal mechanisms of social cognition. These investigations lay the groundwork for enhancing our understanding of the neuronal mechanisms of social behaviors.

More information:

• https://www.dpz.eu/en/social-neurobiology-lab
• https://www.dpz.eu/en