Regarding local brain activity, APOE ε4 carriers with AD exhibit decreased amplitude of low frequency fluctuations (ALFF) in the left hippocampus (Wang et al. 2015) and decreased fractional ALFF (fALFF) in the left insula, left inferior frontal gyrus, and right precentral gyrus (Lin et al. 2017) compared to non‐carriers. Here, APOE is linked to Alzheimer disease.