A thicker-looking visual cortex does not necessarily mean more unused connections

The study compared 24 people born blind with 24 matched sighted participants. Researchers found reduced myelination in the visual cortex, which can alter the apparent boundary between gray and white matter in MRI measurements.

That helps explain why the region can look thicker without requiring the conclusion that normal pruning simply failed. The researchers did not rule out a role for pruning, but found stronger support for a myelination contribution.

The interpretation also follows function. In blind people, this cortex can participate in language, working memory, and other tasks. Structural difference should therefore not automatically be read as impairment. The study shows how improved measurement can revise both a biological explanation and the language used to describe it.