Immunohistochemical analysis indicated a significant decrease in Fos-expressing cells in the dentate gyrus (WT 470.56 ± 37.19 vs. AD 283.79 ± 27.66 cells/mm2, p = 0.0024; Figures 4A–4C) that was also accompanied by elevated expression in CA3 and CA1 (CA3: WT 47.15 ± 13.70 vs. AD 151.66 ± 33.21 cells/mm2, p = 0.0156; CA1: WT 32.55 ± 11.17 vs. AD 88.34 ± 19.01 cells/mm2, p = 0.0299; Figures 4D–4I). This evidence concerns the gene FOS and Alzheimer disease.