Figure 6.
Experiment 5. (A) Experimental protocol. Rats were trained as in former experiments and 72 h later assigned randomly to one of four groups: extinction (R0/E15), control (R0/E0), R1/E14, or R4/E11. Treatments for each group were identical to those in previous experiments. Twenty-four hours later, all groups were again exposed to the training context for 3 min (preshock period) after which they received a single 0.5-mA shock. Twenty-four hours later all groups were subjected to a 5-min test session. (B) Data are the mean ± SEM of percentage time spent freezing during the preshock period of reacquisition and test.
