BDNF and Alzheimer disease: We then focused on the analysis of specific gene clusters highlighted by the KEGG analysis—actin cytoskeleton regulation, endocytosis, chemokine signaling, protein digestion, neurotrophin signaling and genes linked to Alzheimer's disease (AD)—and represented the total amount of genes mapped to the specific KEGG category at each time point (Figure 3c) and the corresponding heat maps (Figure 3d).