Fig. 4.

dCA2 silencing does not disrupt a well-consolidated memory of a littermate but prevents its recall. a Protocol testing effect of dCA2 silencing on retention of a well-consolidated social memory. WT and Amigo2-Cre mice were injected with AAV-DIO-hM4Di-IRES-mCitrine in dCA2. Mice were given CNO IP and randomly divided into two housing cages (A and B). After 24 h, subject mice from cage A were presented with a novel (Nov) mouse and a littermate (Lit) from cage B. b WT and Amigo2-Cre mice spent more time in the chamber housing the novel animal (WT repeated measures one-way ANOVA: n = 10, F(1.414, 12.73) = 44.89, P < 0.0001, Novel vs Littermate P = 0.0114, Tukey’s multiple comparisons test; Cre repeated measures one-way ANOVA: n = 12, F(1.253, 13.79) = 50.15, P < 0.0001, Novel vs Littermate P = 0.0086, Tukey’s multiple comparisons test). The groups did not differ significantly (two-way ANOVA: treatment × chamber F(2,40) = 0.006505, P = 0.9935). c WT and Amigo2-Cre mice showed similar social discrimination scores (unpaired t test: t(20) = 0.03401, P = 0.9732). d Experimental protocol silencing dCA2 during social memory recall. WT and Amigo2-Cre mice previously injected with AAV-DIO-hM4Di-IRES-mCitrine were given CNO IP 30 min prior to the social discrimination trial. e WT mice spent more time in the novel animal chamber compared to the littermate chamber; hM4Di-expressing Amigo2-Cre mice did not show a preference (WT: n = 10, P < 0.0001, Tukey’s multiple comparisons test; Cre: n = 9, P = 0.8026, Tukey’s multiple comparisons test). The groups differed significantly (two-way ANOVA: treatment × chamber F (2,34) = 5.005, P = 0.0124). f Amigo2-Cre mice social discrimination score was significantly lower than that of the WT group (unpaired t test t(17) = 2.391, P = 0.0286). Box-whiskers plots present median (center line), extension from the 25th to 75th percentiles (box) and minimal and maximal values (whiskers). *P < 0.05; **P < 0.01; ****P < 0.0001; ns, P > 0.05