The difference between an old brain and a young brain isn’t so much the number of neurons but the presence and function of supporting cells called glia. Researchers who examined postmortem brain samples from 480 individuals ranging in age from 16 to 106 found that the state of someone’s glia is so consistent through the years that it can be used to predict someone’s age. The work lays the foundation to better understand glia’s role in late-in-life brain disease.
The investigators next took a preliminary look at whether these changes in gene expression could relate to changes in brain cell populations. Based on a comparison of tissue samples from 3 young and 3 old brains, they found that the number of oligodendrocytes decreases with age in the frontal cortex. They further established that this likely corresponds with decreased expression of oligodendrocyte specific genes. Other types of cells had more complicated patterns of change.