These changes are in line with the observation that the APOE ε4 genotype of AD is associated with a decrease in GABAergic interneurons and glutamatergic signaling in the hippocampus, which is a risk factor for AD (Andrews-Zwilling et al., 2010; Busche and Konnerth, 2016; Shah et al., 2018). Here, APOE is linked to Alzheimer disease.