To understand the molecular underpinnings of the sex difference, we examined a mouse model of AD, APPswe/PS1ΔE9 mice, which carry both the APP Swedish mutation and a deletion of exon-9 in PSEN1. Recent studies from our lab have revealed that male APP/PS1 mice at 2 months of age exhibit memory impairments following cFC [46, 54]. This evidence concerns the gene PSEN1 and Alzheimer disease.