APP and Alzheimer disease: In DG (Fig. 6b), there was less TH+ area in 12-month-old APP/PS1 mice compared to 24-month-old WT mice (0.28% ± 0.08% vs 1.3% ± 0.41%, P = 0.0002, Fig. 6d), again suggesting that catecholaminergic fiber degeneration is more greatly affected by AD pathogenesis than by aging.