Fig. 6: CA3-NR1 KO mice exhibited impaired reverberatory activity following CS-US presentation in CS- and Test-CS-responsive CA3 subpopulations under free-moving conditions.
From: Hippocampus as a sorter and reverberatory integrator of sensory inputs
a-c Left, venn diagrams representing (a) CS-, (b) US-, and (c) Test-CS-responsive ensembles. Peri-event raster plots during the training session in each subpopulation of littermate control and KO mice. Each short vertical tick represents a 1 s change of mean z-score across baseline and ten CS-US pairings. Ca2+ activities were aligned at the time that CS-US stimuli were delivered. The color code represents mean z-score. Middle, averaged z-score plots over ten CS-US pairings in each subpopulation. Right, box plots comparing mean z-scores between genotypes in each session (two-tailed unpaired Wilcoxon rank sum test for CS cells: ITI-2, P = 0.00002; ITI-1 latter 9 s, P = 0.012; for US cells: ITI-2, P = 0.00027; for Test-CS cells: US, P = 0.00052; ITI-2, P = 0.0043). d Left, representative binarized raster plots of Ca2+ activity across ten ITI-1 sessions in control animals. Right, magnified raster plots focusing on CS-, US-, and Test-CS-responsive subpopulations and scheme for synchrony analysis. This analysis calculates synchrony by normalizing the number of synchronizations in every 500 ms among three subpopulations in each session. Binarized synchrony data is used for calculation of synchrony rate. e, f Box plots comparing mean synchrony between genotypes in each session. g Synchrony rate between CA1 and CA3 and genotypes (Repeated measures two-way analysis of variance for brain region, F(1,36) = 14.40, P = 0.0006). h Synchrony index during ITI-1 in CA1 and CA3 and genotypes (Repeated measures two-way analysis of variance for brain region × genotype interaction, F(1,36) = 9.441, P = 0.004; two-tailed and adjusted Turkey-Kramer post hoc test for CA1 ctrl vs. CA1 KO, P = 0.0221; for CA1 ctrl vs. CA3 ctrl, P = 0.0063; for CA1 ctrl vs. CA3 KO, P = 0.0472). i, j Mahalanobis PVD and rotation (i) between CS and ITI-1 sessions in the CS-responsive ensemble, and (j) between US and ITI-1 sessions in the US-responsive ensemble (two-tailed Brunner-Munzel test for CS-ITI PVD, P = 0.040; two-tailed unpaired Student’s t test for CS-ITI angle, P = 0.003). Numbers in parentheses denote the (a-c) number of cells or (e-j) mice in each group used for the study. P values were determined using a (a-c) two-tailed Wilcoxon rank sum test (*P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001), (e-f, i-j) an unpaired two-tailed t test (*P < 0.05, **P < 0.01), a (i) two-tailed Brunner-Munzel test (*P < 0.05), or a two-way analysis of variance for (g) synchrony rate and (h) synchrony index with the adjusted and two-tailed Tukey–Kramer test (*P < 0.05, **P < 0.01, ***P < 0.001). Significant effect of hippocampal region for g. N.S., not significant (P > 0.05). Box plots indicate median, first, and third quantiles, and minimum and maximum values. Graphs indicate means ± SEM. In graphs, circles represent individual animals. Detailed statistics are shown in Supplementary Data 1.
