Abnormal, tortuous proximal dendrites and shrunken cholinergic cell soma (Fig. 4D, arrowheads) were also seen in the MSN neurons of aged Thy1-APPL1 compared with non-Tg mice (18 months), as has been reported in multiple AD-like models with endosomal alterations (Cataldo et al., 2000, 2003; Salehi et al., 2006; Choi et al., 2009; Jiang et al., 2016, 2022; Pensalfini et al., 2020). Here, APPL1 is linked to Alzheimer disease.