PSEN1 and Alzheimer disease: It has been shown that 4∼5 month-old APP/PS1 mice do not exhibit any HIPP-dependent memory loss or electrophysiological alteration at this age (Tabassum et al., 2019; Chen et al., 2021), and, indeed, hippocampal abnormalities do not appear until after 6 months of age in these AD-model mice (Viana Da Silva et al., 2016).