Analysis of AP+ cholinergic arbors in the cortex and hippocampus of 62 Chat-IRES-CreER;R26IAP;APP/PS1 brains harvested between one and 12 months of age showed fragmentation of axons and a decrease in AP signal strength (Figure 5A–C), consistent with previously described changes in the appearance of ChAT immunoreactive fibers in mouse and human AD brains (Figure 5—figure supplement 1C,D; Gordon et al., 2002; Schliebs and Arendt, 2011). Here, APP is linked to Alzheimer disease.