For people with dyslexia, rending can be like watching a game of musicalchairs, as words and letters trade places unexpectedly. So until recently, researchers fell safe in assuming that the root of the problem lay in the brain's language centers.
But a new study suggests that a brain region that monitors visual information may he a coconspirator in the syndrome. Using MRI, scientists at the National Institute of Mental Health (NIMH) compared the neuronal activity of dyslexics and nondyslexics as both groups watched random dots shimmy across a video screen. The researchers zoomed in on a grape-sized part of the brain, called V5, that responds to moving images. In normal readers, they found, the moving dots provoked a flurry of V5 activity. But in dyslexics, this region stayed quiet. There were no visible differences between the two groups' brains, though, when they looked at a stationary image, says NIMH researcher Guinevere Eden, Ph.D.
