APOE and Alzheimer disease: Hyperexcitability and swift synaptic plasticity along with decreased background synaptic inhibition have been described in APOE ε4 targeted replacement mice lacking AD pathology and have been suggested as causative for memory and learning impairment exhibited by these mice (Persson et al., 2008; Andrews-Zwilling et al., 2010, 2012; Tong et al., 2016; Nuriel et al., 2017a).