Fig. 3.

Early-life treatment with CRF₁ antagonist improves memory in the relatively stress-free, object recognition test. Data are given as the mean number of seconds (±se) spent exploring each object on d 1 (A) and on d 2 (B), the test day. A, Day 1: upper panel, naive (solid blue bars; n = 9) and vehicle-treated (empty blue bars; n = 6) nonhandled groups; middle panel, naive (solid magenta bars; n = 8) and vehicle-treated (empty magenta bars; n = 3) handled groups. These panels show that object exploration times did not differ between naive and vehicle-treated subgroups. Lower panel, Therefore, the naive and vehicle subgroups were consolidated to compare time spent exploring object 1 (labeled as 1′ for each group) and object 2 (labeled as 2′ for each group). NH, Nonhandled rats; H, handled; NH+A, CRF₁ antagonist-treated nonhandled rats (n = 10); H+A, antagonist-treated handled rats (n = 8). Note that on the first day, all groups explored each object for similar amounts of time. B, Day 2, The ratio of time spent exploring the novel object/time spent exploring the familiar object on d 2. A score of 1 indicates that both objects were explored for similar amounts of time. Administration of CRF₁ antagonist did not modify the ratio of time spent exploring novel vs. familiar objects in handled rats. However, it significantly increased this ratio in the nonhandled rats. *, P < 0.05, significantly different from the nonhandled group. The values of H, H+A, and NH+A groups are not significantly different.