PSEN1 and Alzheimer disease: Recent studies showed that enhancing myelin renewal, by deletion of the muscarinic M1 receptor in oligodendroglia or administration of clemastine, rescued deficits in cognition and hippocampal physiology in APP/PS1 mouse—an AD model overexpressing human amyloid precursor protein (APP) and presenilin-1 (PS1) with mutations associated with early onset familial AD (Chen et al., 2021; Xie et al., 2021).