MAPT and Brain atrophy: PS19 AD/FTD mouse model exhibit Tau aggregation, neuroinflammation, synapse dysfunction, cognitive decline, and brain atrophy in an age-related manner that can be broadly described as presymptomatic at 3 months, early-stage disease at 6 months (sparse Tau pathology and minor changes in behavior), symptomatic disease stage at 9 months (widespread pathology and robust cognitive decline but without widespread neurodegeneration), and end-stage at 11–12 months (robust neuron loss, brain atrophy, and death; Yoshiyama et al., 2007; Dejanovic et al., 2018).