The volume of hippocampus (Heise et al., 2014), electroencephalogram coherence of MTL (Jelic et al., 1997), magnetoencephalography resting state functional connectivity in source space in MTL (Cuesta et al., 2015) and functional connectivity in hippocampal networks (Ye et al., 2018) are conspicuous disrupted in subjects of healthy elderly, aMCI and AD with APOE ε4. This evidence concerns the gene APOE and Alzheimer disease.