Fig. 2: Social subordinate behavior and enhanced social recognition in ELS mice.
a Example of an intra-cage hierarchy structure and social ranks for a single cage with four adult CTR cage-mates tested daily for 6 days in a tube test. Rank stability is observed in both (b) CTR and (c) ELS cages, with rare rank transitions; CTR n = 5 cages, ELS n = 6 cages. d Schematic representation of encounters performed by each animal in a round-robin test, where each animal only competes with mice from other cages in a total of 12 dyadic encounters per trial. e Meta-hierarchy between unfamiliar CTR and ELS adult male mice is represented by the cumulative performance of each animal across each encounter, with error bar representing deviation in encounter outcome across trials; CTR n = 8, ELS n = 8, across 8 RRTT trials. f When compared across time, social subordination in ELS mice presents a stable overall percentage of win–loss encounters when assessing CTR–ELS dyadic encounters; CTR n = 8, ELS n = 8, across 8 RRTT trials. g Heatmap analysis of dyadic encounters reveals a predictable social fingerprint pattern of win–loss outcomes in CTR and ELS animals. h In both ELS cages and CTR cages, the inter-cage meta-hierarchy assessed in the round-robin (RR) is a strong predictor of intra-cage hierarchy. i ELS mice display social subordination in a food competition test when assessing time spent in control of a food pellet after 21 h of food deprivation; CTR n = 8, ELS n = 8. j Total duration for conflict resolution in the tube test was determined as encounter duration in encounters between the three possible dyads: CTR vs CTR (gray), CTR vs ELS (dark red), and ELS vs ELS (red). ELS-ELS dyadic encounters are significantly faster than encounters between ELS–CTR mice or CTR–CTR; CTR n = 8 mice, ELS n = 8 mice; valid dyadic encounters CTR–CTR n = 127, ELS-ELS n = 126, CTR–ELS n = 506. k Encounter duration is independent of the trial outcome in ELS–CTR dyads, as encounter duration is similar when CTR win (CTRW–ELSL: brown) or lose (CTRL–ELSW: yellow); CTR n = 8 mice, ELS n = 8 mice; valid dyadic encounters CTRW–ELSL n = 392, CTRL–ELSW n = 113. In a three-chamber test for social behavior, ELS mice display (l) normal sociability and (m) an increase recognition of social novelty; S1—Stranger 1, E—Empty chamber, S2—Stranger 2; CTR n = 20, ELS n = 20. Statistical comparisons were performed using two-way repeated measures ANOVA (for f), Spearman correlation (for h), unpaired two-tailed t-test (for i, l, m), Kruskal–Wallis test with Dunn’s multiple comparisons test (for j), Mann–Whitney test (for k). Statistical significance was set as *p < 0.05; **p < 0.01; ***p < 0.001. Data are presented as means ± SEM.
