Figure 3. Dorsal CA3 Excitatory Projections to DLS Instruct Fear Responses to Ambiguous Contextual Threats.

(A and B) Schematic of the behavioral timeline.

(C) Schematic illustrating dorsal CA3 infection with CaMKII-eNpHR3.0 and fiber optic implantation on top of anterior DLS in C57B6/J mice.

(D–G) Silencing dorsal CA3 terminals in anterior DLS has no effect on locomotor behavior and innate anxiety in OF (D and E), EPM (F), and NSF (G).

(H and I) Silencing dorsal CA3 terminals in anterior DLS decreases freezing behavior in context B but not A (H), which results in an increase in fear discrimination ratio on block 7 (I). Data (means ± SEM; n = 8,8 mice per group) were analyzed using mixed factor two-way ANOVA (repeated measure over time) followed by Bonferroni’s multiple comparisons post hoc test and log-rank (Mantel Cox) test. *p < 0.05, eNpHR3.0 versus eYFP; #p < 0.05, block 7 versus block 6. Statistics detailed in Table S1.

(J) Schematic representation of the effect of light silencing dorsal CA3 terminals in DLS on brain-wide c-Fos expression 30 min following exposure to context B (day 21). Regions highlighted in red denote a significant effect of eNpHR3.0, and arrows indicate the direction of the effect.

(K and L) Schematic of the behavioral timeline.

(M–O) Silencing dorsal CA3 terminals in anterior DLS increases freezing behavior in context A but not B early on training and (M), and decreases freezing behavior in context B but not A later on training (O) following repeated training in context A (N). Data (means ± SEM; n = 8,10 mice per group) were analyzed using mixed factor two-way ANOVA (repeated measure over time) followed by Bonferroni’s multiple comparisons post hoc test. *p < 0.05, eNpHR3.0versus eYFP. Statistics detailed in Table S1.

See also Figures S1, S2, S3, S5, and S7.