(A-F) Coronal brain sections obtained from mice at 4-6 (A-C) or 20-23 (D-F) months of age were immunostained for NeuN. The number of NeuN-positive cells with neuronal morphology was determined in dentate gyrus (A, D), CA3 (B, E), and CA1 (C, F). n = 11 (A-C) or 18 (D-F) NTG; 11 (A-C) or 5 (D-F) CamKII-tTA; 7 (A-C) or 9 (D-F) hTau-WT(L32); and 14 (A-C) or 10 (D-F) hTau-A152T(L1) mice. *P < 0.05, **P < 0.01, ***P < 0.001 by one-way ANOVA and Tukey test. Values are means ± SEM. 