The latest tools of neuroscience allow us to witness, as never before, the electrical flares, chemical landslides and sluicing of water from zone to zone that alter the geography of the brain as it changes.
Evidence of the ways neural tissue is partially destroyed after a stroke or the onset of dementia has been around for decades. But proof that missing or miswired human brain connections can grow again—what neuroscientists call plasticity—has so far been thin on the ground. In 2014 a study showed that for mice, novel experiences prompt almost immediate changes in white matter—the brain’s connective tissue, or highway system.
Does this structural transformation linked to learning a new skill hold for humans too? The answer appears to be yes. A study just published in the journal Nature Communications found distinct shifts in brain architecture that mirrored the growing reading skills of children with dyslexia.
“The way the connections between different brain regions had changed was startling,” said Jason Yeatman, an assistant professor at the University of Washington who led the study.
Dr. Yeatman’s team, including postdoctoral student Elizabeth Huber, began by recruiting 24 dyslexic children, ages 7 and 12, who had been struggling to learn to read. Few of them could decipher more than simple three-letter words, which largely excluded them from the classroom experience, said Dr. Yeatman.
The researchers thoroughly tested the children’s reading skills and assessed their brain architecture using diffusion magnetic resonance imaging. This noninvasive type of brain imaging tracks how quickly water flows among regions of the brain. It provides a measure of brain density, which increases with the formation of new brain cells, connections and membrane
The children’s initial MRI was followed by three subsequent imaging sessions, evenly spaced over the course of their participation in an intensive, eight-week summer reading program. Designed by the Seattle-based tutoring company Lindamood-Bell, the program provided one-on-one instruction for four hours a day, five days a week. Unlike much recent research on children’s learning, the instruction was in person, not screen-based.
The results showed significant improvement in reading skills—and as the children’s reading fluency increased, large tracts of the white matter in their brains were visibly revamped. “It was not known before that the physical structure and efficiency of the brain could change in just a few weeks,” said Dr. Yeatman.
The instructional approach was, by design, highly individualized and interpersonal. It targets the building blocks of reading and is intended to give children with dyslexia the tools they need to read. But it is just one of several evidence-based, effective approaches. In the future, the researchers hope to compare it to other reading programs to see which features of a curriculum are critical to stimulating rapid changes in white matter.
“It was not known before that the physical structure and efficiency of the brain could change in just a few weeks,” said Prof. Yeatman. “That was one surprising thing.” Another was that the renovation was so pervasive. The researchers expected the observed improvement in the brain’s language areas. “But we also saw changes in the corticospinal tract,” which allows sensation and movement to be sensed by the brain, Dr. Yeatman added.
Perhaps the bond between teacher and child or the frequency and intensity of the teaching program made the difference. It’s hard to pinpoint the cause—or to know how long the neural and behavioral changes will last. But the changes were still impressive.
“We knew it was possible for the brain to change in mice, but we didn’t know the time frame, and we didn’t know how extensive the remodeling was in humans,” said Dr. Yeatman. Now we know that education can physically alter the brains of mice and men—or, more important, boys and girls.