December 9, 2009

Instruction Repairs Brain Connectivity In Poor Readers

Scientists have demonstrated that intensive remedial instruction can bring about a positive change in the brain connectivity of poor readers. The research, published by Cell Press in the December 10th issue of the journal Neuron, has intriguing implications for the therapeutic potential to improve information transfer in multiple neurological abnormalities that are believed to be related to deficits in anatomical connectivity.

The integrity of the brain's white matter, the wiring that facilitates efficient relay of information between different areas of the brain, is absolutely critical to human behavior and cognition. "Although the basic computing power of the brain surely lies in individual neurons, it is only their collective action, made possible by white matter connectivity, that enables the multicentered large-scale brain networks that characterize human thought," explains lead study author, Dr. Timothy A. Keller. "For this reason, even a modest modification in white matter has the potential to enable major changes in cognitive ability."

Previous research has revealed that the brains of children with a reading disability display underactivation of key brain regions involved in reading and suggested that reading difficulty might be linked with impaired connectivity within the brain's reading network. Dr. Keller and colleague, Dr. Marcel Just, used a sophisticated neuroimaging technique to study the white matter of 8- to 10-year-old poor readers before and after intensive remedial instruction. The structural organization of white matter was measured by fractional anisotropy (FA).

Prior to remedial instruction, poor readers had lower FA than good readers in cortical regions associated with reading. These same brain regions exhibited a significantly increased FA in the poor readers after instruction and reading practice, and this increase was correlated with improved reading ability. Importantly, the results also suggested that the amount of fiber-insulating myelin was increased in these cortical areas, an indication that neural transmission is occurring more efficiently.

"Our findings suggest that whatever the cause of abnormally low FA among poor readers may be, the abnormality is amenable to behavioral treatment when provided within an age window in which maturation, experience, and development are still capable of influencing FA," says Dr. Keller. "The capability to improve white matter provides a possible remediation not only for reading difficulty but also for other neurological abnormalities believed to be underpinned by deficits in anatomical connectivity, such as autism."


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