BRAIN-WIDE NEURAL DYNAMICS UNDERLYING SOCIAL DOMINANCE IN MICE

Understanding brain-wide neural dynamics underlying social dominance remains limited. Using multi-fiber photometry, we simultaneously recorded 24 brain regions per mouse during paired dominance interactions.
Aims: We aim to characterize neural activation patterns across brain regions during social dominance behaviors, identifying brain-wide networks and co-activation patterns that support social dominance.
Methods: Mice received photometric fiber array implants targeting 24 brain regions, with pAAV9-SYN-GCAMP6 virus injection for calcium imaging. They later performed Tube Test assay, where paired mice enter opposite ends of a transparent tube, the first to retreat loses. Real-time brain-wide recordings were acquired and synchronized with behavioral tracking then segmented into contact epochs when mice interacted within close proximity.
Results: Data from five groups of mice (3-5 per group, total of 22 mice, 35 pairs) revealed elevated neural activity in specific brain regions, with region-dependent and dynamically timed onsets. Neural responses were more strongly modulated by social identity, specifically the hierarchical rank of the interaction partner, than by the fight outcome itself (win vs. loss). Nucleus accumbens activity increased prior to interactions in which mice won against lower-ranked partners, whereas activity in the prelimbic cortex and amygdala increased before interactions in which mice won against higher-ranked partners. In contrast, widespread post-interaction activation was observed following losses to lower-ranked partners, with increased activity detected across multiple brain regions.
Conclusions: Collectively, these findings suggest that neural dynamics across multiple brain regions encode the social identity of an interaction partner, with distinct circuits engaged before and after social encounters depending on hierarchical context.