Fig. 4: Early social environment influences WT and Shank3 KO mice differently in the Live Mouse Tracker.

In the Live Mouse Tracker, WT mice (gray; n = 21, 13 males and 8 females) and Shank3 KO mice (turquoise; n = 26, 15 males and 11 females) spent less time in nose contacts (A, D), huddling (B, E) and social approach (C, F) with their cage mates (Trial 1; lighter color) than with a mix of 2 unknown KO and 2 unknown WT mice (Trial2 WT + KO), or with 4 unknown KO or WT mice separately another day (Trial3 WT or KO; darker color). Shank3 KO mice showed increased nose contacts (A) and huddling (B) when interacting only with Shank3 KO mice in Trial 3, compared to Trial 2, while WT exhibited increased nose contacts only. Both Shank3 KO and WT mice spent comparable amounts of time in social approach, regardless of the trials (C). In Trial 3, Shank3 KO mice raised in groups of 2 (light turquoise; n = 6 females) showed increased nose contacts (D) and huddling (E) behavior compared to WT mice raised in groups of 2. Conversely, Shank3 KO mice raised in groups of 4 (dark turquoise; n = 6 males) exhibited reduced nose contacts and social approach (F) than their WT counterparts. Social exploration in Shank3 KO mice differed between groups of 2 and 4, but not in groups of 3 (turquoise; n = 4, 2 males and 2 females). Data are presented as mean ± sd (Table S3, sex effect in Fig. S5). Statistical analysis was performed using a linear model followed by pairwise comparisons using the estimated marginal means, with asterisks indicating genotype effects and hash symbols indicating trial (A–C) or housing (D–F) effects (p = P adjusted in all tests). * or #: p < 0.05, ** or ##: p < 0.01, *** or ###: p < 0.001, **** or ####: p < 0.0001.