In the open field, socially-isolated rats spent less time in the center of the open field relative to group-reared rats (Rearing main effect: F1,28 = 10.56, P = 0.003; η2 = 0.265; Fig. 1a). Isolates excreted more fecal boli in the open field compared to group-reared rats (Rearing main effect: F1,28 = 13.46, P = 0.001; η2 = 0.196; Fig. 1b). In the elevated plus maze, isolates exhibited a lower % time in the open arms (Rearing main effect: F1,28 = 17.87, P = 0.000; η2 = 0.322; Fig. 1d) and a greater % time in the closed arms (Rearing main effect: F1,28 = 14.42, P = 0.001; η2 = 0.303; Data not shown), compared to group-reared rats. The number of closed arm entries was unaltered in isolates relative to socially-reared rats (P = 0.003; Data not shown). In the elevated plus maze, isolates also engaged in fewer stretch-attend postures (Rearing main effect: F1,28 = 105.33, P = 0.000; η2 = 0.769; Data not shown) and head dips (Rearing main effect: F1,28 = 18.40, P = 0.000; η2 = 0.412;
