Fig. 5
Over-activation of hippocampal neurons following long term memory retrieval in neurogenesis-depleted Nestin-δ-HSV-TK mice (a) Experimental design. Nestin-δ-HSV-TK mice (N = 4) were fed with vehicle or valganciclovir chow following weaning for six weeks before performing pattern separation testing. Ten days after behavioral testing, a single probe test, where the mouse was placed only in the shock context A, was performed. Then, the animals were sacrificed for analysis of changes in Egr-1 (zif268) expression in the hippocampal circuitry. b-d Quantification of Egr-1 positive cells in the hippocampus. The total number of Egr-1 positive cells showed a trending increase in the granular cell layer of the dentate gyrus (b), with significant increases in the CA3 region (c) (one-tailed, unpaired t-test; t 4 = 2.302, P = 0.0414), and the CA1 region (d) (one-tailed, unpaired t-test; t 6 = 2.039, P = 0.0438). e-h Images of DAPI + Egr-1+ cells in the CA3 (e, f) and Egr-1+ cells in the CA1 (g, h) regions of vehicle- or valganciclovir-treated Nestin-δ-HSV-TK mice reveal more Egr-1+ cells in the valganciclovir-treated Nestin-δ-HSV-TK mice. Scale bar = 15 μM (E,F), 75 μM (g, h)