We found that primate-specific DEGs were enriched in different pathways in the AST of the SN, including APC, ITPR2, and PIK3R1, which are related to Alzheimer's disease, as well as ERBB4, FGFR1 and FYN, which are associated with diseases related to signal transduction by growth factor receptors and second messengers (Fig. 4F) [64, 65]. Here, PIK3R1 is linked to early-onset autosomal dominant Alzheimer disease.