In Alzheimer's disease (AD) mice, some reports have indicated that APα promotes the proliferation of NPCs in the LV‐SVZ, and prevents the reduction of tyrosine hydroxylase (TH)‐expressed neurons in SN pars compacta (SNpc).8, 10, 14, 15, 16. This evidence concerns the gene TH and early-onset autosomal dominant Alzheimer disease.