Fig. 4

Resident–intruder agonistic interactions in resident’s home cage. a, b Number of fights (a) and duration of contacts (b) initiated by WT and mdx residents. There was no effect of resident’s genotype on these parameters, but note that the expression of agonistic and affiliative behaviors differed depending on the genotype of the intruder mice (e.g., less fights and longer interactions with C3H intruders). c, d Intruders’ behavior varied depending on the genotype of the resident mice, as shown by shorter latencies (c) and slightly longer duration of social contacts when confronted with mdx mice (d). e The number of dominant acts (i.e., putting a paw on the resident’s head or back) differed depending on the resident’s genotype, as illustrated by the opposite effects shown in the non-aggressive C3H intruders compared to the aggressive balb/c intruders. f Fear responses in resident mice, expressed as time spent freezing during social interactions, were more prominent during confrontation with non-aggressive C3H intruders and enhanced in mdx compared to WT resident mice. *p < 0.05