APP and Alzheimer disease: A previous study reported that the APP-a7KO model (Tg2576 mice expressing the human amyloid precursor protein sequence with the Swedish mutation crossed with α7 nAChRs null-mutant) have worsened cognitive deficits when α7 nAChR is absent, and a decrease of α7 nAChRs levels are associated with synaptic damage in AD patients [19].