Do Dyslexic Brains Cause Reading Problems, or Vice Versa?

Magnetic source imaging (MSI) (functional magnetic resonance imaging—fMRl) allows scientists to detect which parts of an individual's brain are active when an individual is performing a particular task. With MSI, researchers can examine what parts of many people's brains are used during, for example, the reading of words. If individuals with dyslexia are using different parts of their brains than individuals who read normally, then there must be an association between the MSI-revealed activities of the brain used by the different groups and the reading performance of those groups. For individuals with dyslexia, MSIs show, for example, that many more areas of the brain are activated than for normally reading individuals. A natural interpretation is that this reflects different biological structure in the brains of people with reading problems.

An alternative interpretation is that instead of the brain making it possible for children to learn from instruction, instruction may program the brain! Studies that describe the functioning of the brain before and after remedial reading intervention show that this possibility, which seemed so improbable in the last millennium, may be accurate (Simos et ai., 2002; Temple et al., 2003). These studies show that as children learn to read, the MSI data for their brains become more organized, looking more and more like the brains of normal readers.