Fig. 3.

The male brain undergoes more global gene change than the female brain during aging [(20–59 yrs) vs. (60–99 yrs)]. (A) Gene change was assessed independently for males and females. Relative to females, males showed more than three times as many gene changes globally across the brain and more down-regulated than up-regulated genes. (B) Patterns of global gene changes over 20-year increments reveal that males underwent substantial gene change in the transition to the sixth and seventh decades of life, whereas females showed relatively few gene changes at this age range. In contrast, whereas gene expression appears to be stable after age 80 in the male brain, females show more gene changes with increasing age, with the largest numbers of genes responding across the brain in the eighth and ninth decades.