Figure 2.

Odor-shock cue conditioning increases freezing to odor during training. Total cumulative (seconds) freezing (±SEM) during paired odor-shock cue conditioning at (A,B) PN18 (Control: Alone n = 8; Mom n = 8; LB: Alone n = 8; Mom n = 8) and (C,D) PN28 (Control: Alone n = 9; Mom n = 8; LB: Alone n = 14; Mom n = 15). Cue conditioning increased freezing at both ages in both control and low bedding (LB) rearing conditions however increased freezing was observed in animals conditioned with the mom (except in PN28 Control group) relative to animals conditioned alone. Open circle = conditioned with the mom; filled circles = conditioned alone; blue = controls; red = LB. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001.