PSEN1 and Alzheimer disease: We injected Aβ into the hippocampus of Gca‐Cre‐EGFP mice to establish an AD mouse model.[14] We verified that Aβ oligomerization was formed during incubation period in vitro, and Aβ level in Aβ injection‐induced AD mice model was comparable to that in 6‐month‐old APP/PS1 mice.