PSEN1 and Alzheimer disease: Concordant with heightened central inflammatory signature of AD pathology9,39, microglia density was substantially higher in the hippocampal CA1 (Fig. 4A,B) and CA3 (Fig. 4E,F) regions as well as the cortex (Supplemental Fig. 4A,B) in APP/PS1 mice when compared with their WT counterparts at 7 months of age.