Fig. 3: Foraging and escape behaviors during tone testing.

a The mean latency (±SEM) to procure the pellet during the pre-tone baseline trials on testing day 1 (D-1). Both O-S and T/O-S groups took significantly longer times to exit (gate opening, t = 0) and return to the nest with the pellet than T-S and T-O groups (Kruskal–Wallis, H = 20.518, p < 0.001; pairwise comparisons, P = 0.003 for T-S vs. T/O-S, p < 0.001 for T/O-S vs. T-O, p = 0.013 for T-S vs. O-S, p < 0.001 for O-S vs. T-O). b The times (mean ± SEM) to leave nest and reach trigger zone on day 1 tone test trials. Both O-S and T/O-S groups had longer latencies to leave nest (Kruskal–Wallis, H = 27.071, p < 0.001; pairwise comparisons, p = 0.003 for T-S vs. T/O-S, p < 0.001 for T/O-S vs. T-O, p = 0.044 for T-S vs. O-S, p < 0.001 for O-S vs. T-O. Once outside the nest, the T/O-S group took longer time to reach the trigger zone than the T-S and T-O (Kruskal–Wallis, H = 9.153, p = 0.027; pairwise comparisons, p = 0.019 for T-S vs. T/O-S, p = 0.042 for T/O-S vs. T-O). During the tone test, the latencies to procure the pellet within the 60 s allotted time were significantly longer in O-S and T/O-S animals compared to T-S and T-O animals (Kruskal–Wallis, H = 34.428, p < 0.001; pairwise comparisons, p < 0.001 for T-S vs. T/O-S, p < 0.001 for T/O-S vs. T-O, p = 0.002 for T-S vs. O-S, p < 0.001 for O-S vs. T-O). c The mean latency (±SEM) to procure the pellet during the pre-tone baseline trials on testing day 2 (D-2). O-S and T/O-S groups continued to have longer latencies to exit (gate opening, t = 0) and return to the nest with the pellet than T-S and T-O groups (Kruskal–Wallis, H = 12.47, p = 0.006; pairwise comparisons, p = 0.022 for T-S vs. T/O-S, p = 0.002 for T/O-S vs. T-O, P = 0.009 for O-S vs. T-O). d The times (mean ± SEM) to leave nest and reach trigger zone on day 2 tone test trials. There were group differences in the latencies to leave nest (Kruskal–Wallis, H = 21.505, p < 0.001; pairwise comparisons, p = 0.001 for T-S vs. T/O-S, p < 0.001 for T/O-S vs. T-O, p = 0.002 for O-S vs. T-O). Once outside the nest, there were group differences in the latencies to reach the trigger zone (Kruskal–Wallis, H = 21.531, p < 0.001; pairwise comparisons, p < 0.001 for T-S vs. T/O-S, p < 0.001 for T/O-S vs. T-O, p = 0.037 for O-S vs. T-O). During the tone test, the latencies to procure the pellet within the 60 s allotted time were significantly longer in O-S and T/O-S animals compared to T-S and T-O animals (Kruskal–Wallis, H = 37.223, p < 0.001; pairwise comparisons, p < 0.001 for T-S vs. T/O-S, p < 0.001 for T/O-S vs. T-O, p < 0.001 for T-S vs. O-S, p < 0.001 for O-S vs. T-O). e Individual track plots from all animals from each group displaying the XY trajectory coordinates each rat took during the first tone exposure. The parenthesized numbers next to plots represent the trial(s) needed for successful foraging. f The overall success rates of procuring the pellet on the first testing day were significantly lower in the O-S and T/O-S groups compared to the T-S and T-O groups (Kruskal–Wallis, H = 32.299, p < 0.001; pairwise comparisons, p < 0.001 for T-S vs. T/O-S, p < 0.001 for T/O-S vs. T-O, p = 0.001 for T-S vs. O-S, p = 0.003 for O-S vs. T-O). g The O-S and T/O-S animals required extended trials to obtain the pellet (Kruskal–Wallis, H =  = 32.004, p < 0.001; pairwise comparisons, p < 0.001 for T-S vs. T/O-S, p < 0.001 for T/O-S vs. T-O, p = 0.002 for T-S vs. O-S, p = 0.011 for O-S vs. T-O). h In T-S and T/O-S animals, there were no reliable correlations (Spearman’s correlation coefficient) between the tone-induced suppression of pellet procurement (an index of fear) and the temporal intervals (i.e., ISIs) between tone CS onset and shock US onset in neither testing day 1 nor 2 (* compared to both O-S and T/O-S, p < 0.05, **p < 0.01, ***p < 0.001; # compared to T/O-S, p < 0.05, p < 0.01).