Our ability to read depends on the communication between distant areas of the brain, such as those involved in vision, hearing, and language. Research published this week (October 8) in the Proceedings of the National Academy of Sciences reveals that the growth pattern of connections between these areas can predict how a child’s reading skills will develop—a finding that could lead to teaching strategies most appropriate for kids at different stages of development.
Neuroscientists at Stanford University in California studied the reading skills of 55 children, aged 7 to 15, over a 3-year period. They also took MRI scans of the children’s brains at least 3 times during that period to visualize the growth of two major white-matter tracts—bundles of nerve fibers that connect brain regions. They found that differences in the growth of these tracts predicted variations in reading ability.
White-matter growth is governed by two processes: pruning, in which extraneous nerve fibers and neuronal connections are eliminated, and myelination, in which nerve fibers in the tracts are surrounded by fatty tissue that increases the speed with which they transmit electrical signals. Both are in part determined by experience, so they happen at different times in different people.
“We think the relative timing of pruning and myelination differs between strong and weak readers,” Stanford’s Jason Yeatman, one of the study authors, told Nature. “In good readers, both processes are unfolding together at an even rate. In poor readers, the two processes are out of sync. You have rapid, early growth, and the tracts develop before [the children] even start learning to read.”
Yeatman added that in future it might be possible to see when pruning is taking place, a period in which children may find it easier to learn to read, and tailor lessons accordingly.