Why do women’s brains stay healthier longer?
Could researchers have uncovered a key reason why women tend to outlive men and retain cognitive abilities as they age? Previously thought to be mostly inactive, a second X chromosome may have a built-in advantage.
What scientists discovered:
Women inherit two X chromosomes, but one is typically silenced in cells known as a Barr body. Scientists found that in aging female mice—equivalent to 65 human years—this silent X reactivates certain brain-supporting genes. This may help explain why women’s brains show less cognitive decline than men’s.
Researchers tracked gene activity in the hippocampus of aged female mice and found about 20 reactivated genes from the inactive X, many tied to brain development and cognition. PLP1 stood out for its role in myelin production, which protects nerve fibers. Older female mice had higher PLP1 levels than males, and with increased PLP1 improved learning and memory in both sexes, suggesting a potential way to enhance brain function with age.
Similar patterns were found in human brain tissue, with older women showing higher PLP1 levels in the same regions as mice. This suggests a shared protective mechanism that could inform strategies to slow cognitive decline in both sexes. While more research is needed, the study highlights the female brain’s resilience and the X chromosome’s potential in aging.