The 3xTg-AD entorhinal cortex harbors an increased number of macrophages/microglia at 6 months of age. Coronal brain sections from 2 and 6 month-old 3xTg-AD and control mice were stained with anti-F4/80 antibody and developed using DAB. (A) Qualitative image analysis reveals activation of F4/80-expressing macrophages and microglia specifically in the entorhinal cortex of 3xTg-AD mice at 6 months of age. (B) Unbiased quantitative stereologic analyses were performed on the entorhinal cortex to derive the total number of F4/80-positive cells. Error bars indicate standard deviation. N = 4 per genotype per time point. "*" indicates p < 0.008. The scale bar represents 50 μm.