Fig. 5: Optical silencing of PPC ensemble activity dissociates the pre-exposed context-IS association without affecting original memories.

a Labeling of PPC neurons in c-fos-tTA transgenic mice with the LVs TRE3G-ArchT-EYFP or TRE3G-EYFP. b The behavioral experiment with optical silencing (top). Blue and gray bars indicate the presence or absence of Dox, respectively. Optical silencing (15 min) to the PPC was delivered in the home cage immediately after test 1. The left graph shows the freezing level at conditioning, reactivation, test 1, and test 2 (bottom) (ArchT-Light OFF, n = 11 mice, ArchT-Light ON, n = 11 mice, EYFP-Light ON, n = 13 mice) (two-way ANOVA with RM followed by Sidak’s post hoc test, session: P < 0.0001, group: P = 0.0939, session × group: P = 0.0008). The right graph shows the freezing level of each group at test 2 (one-way ANOVA followed by Tukey’s post hoc tests, P < 0.0001). Mice were sacrificed 90 min after test 2 for immunohistochemistry (Fig. 6e, f). c The behavioral experiment with 15 min optical silencing (top). Optical silencing to the PPC was delivered in the home cage immediately after test 1. Lidocaine was injected in the CA1 region 15 min before test 3. The graph shows the freezing level at conditioning, reactivation, test 1, and test 2 (left), and motility during the conditioning, reactivation, test 1, test 2 and test 3 (right) (Vehicle in CA1, n = 16 mice, Lidocaine in CA1, n = 17 mice) (two-way ANOVA with RM followed by Sidak’s post hoc test, freezing; session: P < 0.0001, group: P = 0.3449, session × group: P = 0.4925, motility; session: P < 0.0001, group: P = 0.0322, session × group: P < 0.0001). d The behavioral experiment with 15 min optical silencing (top). Optical silencing to the PPC was delivered in the home cage immediately after test 1. Lidocaine was injected in the BLA 15 min before test 3. The graph shows the freezing level at conditioning, reactivation, test 1, and test 2 (left), the interaction time (center) and the latency to the first interaction (right) in test 3 (bottom) (Vehicle in BLA, n = 13 mice, Lidocaine in BLA, n = 13 mice) (two-way ANOVA with RM followed by Sidak’s post hoc test, Freezing; session: P < 0.0001, group: P = 0.4608, session × group: P = 0.4670, interaction time; time: P = 0.0028, group: P = 0.0003, time × group: P = 0.2251, two-tailed unpaired t test, latency to 1st interaction; P = 0.0060). Error bars represent the mean ± s.e.m. *P < 0.05. Ctx context, IS immediate shock, IHC immunohistochemistry. For details of statistical data, see Supplementary Table 1. Source data are provided as a Source Data file.