Fig. 5: Inhibitory activity during recall is critical for memory selectivity.
From: Dynamic and selective engrams emerge with memory consolidation
a, Schematic of simulation protocol with blockage of inhibitory neurons during recall. b–d, Means and 99% confidence intervals are shown. n = 10 trials. Color denotes stimulus as in Fig. 1c. b, Firing rate of engram cells averaged across all cue presentations during recall in a as a function of consolidation time (Methods). Dashed line indicates threshold ζthr = 10 Hz for engram cell activation. c, Memory recall in a as a function of consolidation time. d, Discrimination index between recall evoked by cues of the training stimulus and individual novel stimuli in a as a function of consolidation time (Methods). e, Schematic of experimental protocol with optogenetic inhibition of DG CCK+ interneurons. f,g, Means and 99% confidence intervals are shown. f, Freezing levels during memory recall in e as a function of delay time. Top, control group. Bottom, CCK+ inhibition group. Two-sided Wilcoxon signed-rank test between freezing in the training and neutral contexts. Control, n = 7 mice per group. CCK+ inhibition, n = 9 mice per group. g, Discrimination index between freezing levels in the training and neutral contexts in f (Methods). Two-sided one-sample Wilcoxon signed-rank test against discrimination = 0. Control, n = 7 mice per group. CCK+ inhibition, n = 9 mice per group. h, Schematic of experimental protocol with optogenetic inhibition of DG PV+ interneurons. i,j, Means and 99% confidence intervals are shown. i, Freezing levels during memory recall in h as a function of delay time. Top, control group. Bottom, PV+ inhibition group. Two-sided Wilcoxon signed-rank test between freezing in the training and neutral contexts. Control, n = 7 mice per group. PV+ inhibition, n = 9 mice per group. j, Discrimination index between freezing levels in the training and neutral contexts in i. Two-sided one-sample Wilcoxon signed-rank test against discrimination = 0. Control, n = 7 mice per group. PV+ inhibition, n = 9 mice per group. f,g,i,j, *P < 0.05; NS, not significant. For detailed statistical test results, see Supplementary Table 1.
