CHAT and Alzheimer disease: The Ts65Dn mouse model recapitulates many of the endophenotypes of DS and AD, including hippocampal-dependent learning and memory deficits, BFCN degeneration and septohippocampal circuit dysfunction, notably CA1 pyramidal neuron and choline acetyltransferase (ChAT) activity deficits (Granholm et al., 2000; Belichenko et al., 2004, 2009; Kelley et al., 2014a,b).