APP and Alzheimer disease: In our own experience, most of the housed APP/PS1 mice indeed developed AD features at 6 months of age, and thus the time point at 5 months of age was selected for this study, since we aimed to examine the accelerating development of AD by SEVO, and the SEVO-induced behavioral disorder and pathological changes at 6 months of age may be concealed or weakened due to the automatic disease progression.