Dynamical Representation of Dominance Relationships in the Human Rostromedial Prefrontal Cortex

• Published in: Current biology Vol. 26; no. 23; pp. 3107 - 3115
• Main Authors: Ligneul, Romain, Obeso, Ignacio, Ruff, Christian C., Dreher, Jean-Claude
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 05.12.2016; Elsevier
• Subjects: Cognitive science; Electric Stimulation; fMRI; Humans; Learning; locus of control; Magnetic Resonance Imaging; mPFC; Neuroscience; Prefrontal Cortex - anatomy & histology; Prefrontal Cortex - diagnostic imaging; Prefrontal Cortex - physiology; reinforcement-learning; Social Dominance; social hierarchy; social learning; tDCS; ventral striatum; social dominance; fMRI; reinforcement-learning; mPFC; performance; tDCS; ventral striatum; locus of control; social learning; social hierarchy
• ISSN: 0960-9822; 1879-0445
• DOI: 10.1016/j.cub.2016.09.015

Humans and other primates have evolved the ability to represent their status in the group’s social hierarchy, which is essential for avoiding harm and accessing resources. Yet it remains unclear how the human brain learns dominance status and adjusts behavior accordingly during dynamic social interactions. Here we address this issue with a combination of fMRI and transcranial direct current stimulation (tDCS). In a first fMRI experiment, participants learned an implicit dominance hierarchy while playing a competitive game against three opponents of different skills. Neural activity in the rostromedial PFC (rmPFC) dynamically tracked and updated the dominance status of the opponents, whereas the ventromedial PFC and ventral striatum reacted specifically to competitive victories and defeats. In a second experiment, we applied anodal tDCS over the rmPFC to enhance neural excitability while subjects performed a similar competitive task. The stimulation enhanced the relative weight of victories over defeats in learning social dominance relationships and exacerbated the influence of one’s own dominance over competitive strategies. Importantly, these tDCS effects were specific to trials in which subjects learned about dominance relationships, as they were not present for control choices associated with monetary incentives but no competitive feedback. Taken together, our findings elucidate the role of rmPFC computations in dominance learning and unravel a fundamental mechanism that governs the emergence and maintenance of social dominance relationships in humans. [Display omitted] •Social dominance is learned by a reinforcement-learning process•Social dominance status and associated prediction errors are encoded in the rmPFC•rmPFC stimulation shifts the weight of victories and defeats for dominance learning Ligneul et al. demonstrate that BOLD activity in the rmPFC represents social dominance relationships as learned from competitive interactions, whereas the vmPFC and ventral striatum encode social victories and defeats, respectively. Electrical stimulation of the rmPFC modulates learning and updating of social dominance representations.