Extinction and rapid reacquisition prior to immunohistochemistry. (A) Overview of the design of Experiment 4. The times listed represent the total time of exposure to the context for a given session. A “+” sign indicates a single 0.75 mA shock and a “−” sign indicates the exposure to the context without shock. (B) The acquisition and extinction curves from Groups REC-EXT and REC-NO EXT as shown by the mean percent freezing for each session; A = acquisition session, E = extinction session (C) Mean percent freezing in the 30 sec pre- and postshock on Day 6 during reconditioning. Rapid reacquisition of freezing relative to initial acquisition occurred in both REC groups, but only in REC-EXT relative to preshock freezing. Significance between groups is represented by (***) P < 0.001; (*) P < 0.05. REC-EXT, n = 6; REC-NO EXT, n = 6; COND, n = 6; HAND, n = 6. Error bars represent standard error of the mean.
