Freezing response in Context B. Data are presented as mean + SEM percent time in Experiment 1. Sexes are collapsed due to the absence of significant sex differences but are represented by individual data points (open circles = males; solid triangles = females). (A) During the 5 min single shock session in Context B, rats in the 15-shock group exhibited significantly greater freezing behavior compared to the 0-shock controls. Regardless of shock group, all rats displayed a significant increase in freezing behavior at the post-shock timepoint (32 sec window, four samplings) compared to the pre-shock timepoint (32 sec window, four samplings). (B) When re-exposed to Context B during the 12 min stress-enhanced fear learning (SEFL) tests, Test 1 (left panel) conducted 24 h later and Test 2 (right panel) conducted 30 days later, the 4- and 15-shock groups exhibited heightened freezing behavior relative to 0- and 1-shock groups. These shock group differences persisted despite an overall reduction in freezing behavior from Test 1 to 2. (*) P < 0.05.
