Effects of combination of intra-amygdala infusions of ChABC and extinction training on the subsequent learning of new morphine-induced CPP. A, Timeline of experimental procedure. B, C, ChABC (0.01 U/side) microinfusions into the BLA or CeA 1 d after the postconditioning test in conjunction with extinction training had no effect on the subsequent relearning of morphine-induced CPP. No significant difference was found in the new morphine-induced CPP test between the ChABC group and the naive group. The data are expressed as the mean ± SEM preference scores in seconds (time spent in the morphine-paired chamber minus time spent in the saline-paired chamber) during the CPP tests (n = 7–8 per group). Post-C1, Postconditioning test 1; Post-E, postextinction test; Post-C2, postconditioning test 2.