
Research, Blind Can Redirect Visual Part of Brain
Rather than lying dormant, visual areas in the brains of those who are blind are reassigned to process non-visual information.In a new study, researchers explain that because blind people don't need to interpret visual images, the visual cortex in their brains processes verbal information instead.
"Basically, the study suggests that the visual cortex can be put to use in other non-visual tasks when the retina is dysfunctional from birth," says Ehud Zohary of Hebrew University in Jerusalem.
Zohary says previous research had shown the visual cortex was active during Braille reading, but researchers believed the visual cortex was responding to the sense of touch used for Braille. The new study shows the visual cortex may instead be responding to non-sensory cues and appears to be processing verbal tasks.
For this study, published in the July issue of Nature Neuroscience, 10 people who had been blind since birth underwent functional magnetic resonance imaging.
Participants did memory exercises and listened to words. They also read Braille words and then meaningless groups of Braille letters to see if their visual cortexes were responding to touch or to the words. For comparison, seven people with normal vision completed the tasks wearing a blindfold.
The researchers found that in blind people, the visual cortex was most active when performing verbal memory tasks."The blind as a group seem to be better than their sighted peers in their verbal memory skills," Zohary says.
Neurologist A. Robert Spitzer, from William Beaumont Hospital in Royal Oak, Mich., says, "What this is saying is that the brain can be rewired to perform completely different functions."