Brain cortex structure reveals aging patterns across the lifespan

The cerebral cortex varies across regions in its thickness and in the amount of myelin, a fatty substance that wraps nerve fibers and speeds up signals. Researchers asked whether this variation forms a readable fingerprint of how the brain is organized and how it ages.

Two structural gradients in the cortex

The researchers analyzed MRI data from three large datasets covering people aged 5 to 100 years. Using the visual cortex as a test case, they identified two distinct architectural gradients: regions where cortical thickness and myelin density change in tandem, and regions where they diverge.

Both gradients predicted the functional layout of the visual system, running parallel to known processing regions. The convergent gradient reflected the hierarchical organization of visual processing, from simpler to more complex information. The divergent gradient even pointed to visual representations not previously described.

Different aging trajectories

The two gradients followed different lifespan trajectories: they changed at different times and in different ways between ages 5 and 100. This suggests the cortex does not age uniformly; different structural aspects each have their own developmental timeline.

The researchers propose that architectural gradients could offer a measurable, non-invasive way to understand brain organization and development across the lifespan via MRI.

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