Fig. 6: Lack of synaptic potentiation of the vCA1–BA pathway under anisomycin-induced retrograde amnesia.

a Experimental setup for b–g. b Mice were exposed to Context A to induce ChR2 expression in vCA1 neurons active in Context A. They were then fear conditioned in Context A for tdT expression in BA fear neurons and received anisomycin (ANI, 10 mice) or saline injections (SAL, 7 mice). c Comparison of freezing behavior in Context A 24 h after fear conditioning between groups (two-sided unpaired t-test). d Left: image showing ChR2-eYFP-expressing vCA1 neurons (green, circles). Right: image of a pair of BA neurons, one tdT+ (red) and one tdT−, loaded with biocytin during recording and labeled with streptavidin-Alexa Fluor 633 (green). e Left: traces of EPSCs recorded in tdT− and tdT+ BA neurons in the saline control group. EPSCs were induced with photostimulation of Context A vCA1 inputs and recorded as in Fig. 4d. Middle: comparison of the AMPA/NMDA (A/N) ratios between tdT− and tdT+ neurons. Two-way ANOVA with post hoc comparisons was used to analyze combined data in e and f. Right: scatter plot of the A/N ratios in 22 pairs of tdT− and adjacent tdT+ cells in the saline control group. f Left: traces of EPSCs recorded in tdT− and tdT+ BA neurons in the anisomycin group. Middle and Right: comparison of AMPA/NMDA ratios between tdT− and tdT+ neurons in the anisomycin group (p = 1.00, two-way ANOVA with post hoc comparisons). g The average difference in AMPA/NMDA ratio between tdT+ and tdT− neurons in each mouse positively correlated with freezing behavior during memory recall (Pearson correlation test). h Experimental setup for i and j. mCherry was expressed in BA and vCA1 neurons active during contextual fear conditioning (FC group) or those active in the home cages (HC group). Neurons active during fear memory recall were immunostained for c-Fos. i Images showing BA and vCA1 neurons labeled with mCherry (red) and c-Fos (green). Both mCherry+ and c-Fos+ neurons were marked with circles. j Comparison of c-Fos+ proportion among all mCherry-labeled BA and vCA1 neurons (two-sided unpaired t-test). n = 5–7 mice per group. Error bars represent the SEM. Source data are provided as a Source Data file. See also Supplementary Figs. 14–15.