Figure 2.

Early-life experiences bidirectionally modulate peer-play behavior. (A) Schematic of an example rat peer-play posture, known as pinning. The total play duration graphed in (B,C) consists of the summed duration in seconds of all play behaviors, including pinning, pouncing, chasing/following, boxing, and kicking, that a late-adolescent male experimental rat performs, directed toward a juvenile same-sex conspecific, during a 10-min test of social interaction in an open field. (B) Fragmented, unpredictable maternal care (LBN) provokes anhedonia, shown here as decreased peer play in a test of social interaction. Data are mean ± SEM; n = 5/group; t-test with Welch’s correction for unequal variance, t_(4.169) = 2.879, *p < 0.05. (C) Augmented, predictable maternal care (AUG) results in increased peer play in late adolescence. Data are mean ± SEM; n = 5/group; t-test with Welch’s correction for unequal variance, t_(4.070) = 2.788, *p < 0.05.