in Figure S1. This analysis indicated that the same major biological process reflected in the gene expression started in normal brains and continued developing in AD brains. We found a significant correlation of PC1 with chronological age in non-demented individuals (ρ = 0.58, p = 9E–13) and concluded that this gene expression pattern captures normal aging processes in prefrontal cortex. Interestingly, this correlation did not exist in AD patients (ρ = 0.10, p = 0.17). Table S2 contains the lists of genes that were most up- and downregulated with age and were selected based on the strongest absolute correlations with PC1.
