Fig. 3

dCA2 is necessary for social memory encoding and consolidation. a Diagram illustrating injection of AAV-DIO-eArch3.0-eYFP into dCA2 of Amigo2-Cre and WT littermates. An optic fiber was implanted above dCA2. b Dorsal HPC coronal section from an Amigo2-Cre mouse expressing eArch3.0-eYFP in dCA2 (green). Arrow indicates optic fiber tip location, above dCA2. c Behavior protocol for testing whether dCA2 is required for social memory encoding. Green light was delivered through the optic fiber during the 2 min of trial 1 of a direct interaction test. Trial 2 was performed 30 min later with light off. d WT mice displayed decreased social exploration during trial 2 (WT: n = 14, P = 0.0074, Sidak’s multiple comparisons test) whereas Amigo2-Cre mice did not (Cre: n = 10, P = 0.9371, Sidak’s multiple comparisons test). The groups differed significantly (two-way ANOVA: treatment × trial F(1,22) = 5.482, P = 0.0287). e Percent reduction in social exploration time was lower in Amigo2-Cre mice than WT littermates (unpaired t test: t(22) = 2.590, P = 0.0167). f Protocol for determining whether dCA2 is needed during memory consolidation with a direct interaction test. WT and Amigo2-Cre littermates were injected in dCA2 with AAV-DIO-hM4Di-IRES-mCitrine. CNO was given IP 12 min after trial 1, with trial 2 performed 24 h later. g Only WT mice displayed social memory (WT: n = 16, P = 0.0045, Sidak’s multiple comparisons test; Cre: n = 15, P = 0.9797, Sidak’s multiple comparisons test). The groups differed significantly (two-way ANOVA: treatment × trial F(1,29) = 6.058, P = 0.020). h Percent reduction was lower in Amigo2-Cre compared to WT group (unpaired t test: t(29) = 2.173, P = 0.0381). Results in d and g show mean ± s.e.m. Box-whiskers plots in e and h present median (center line), extension from the 25th to 75th percentiles (box) and minimal and maximal values (whiskers). *P < 0.05; **P < 0.01; ns, P > 0.05. Scale bar, 250 µm (b)