THE visual cortex of a blind person鈥檚 brain does not remain
idle鈥攐ther senses take it over, say scientists at the National Institutes
of Health in Bethesda, Maryland.
Leonardo Cohen and his colleagues asked ten blind and five sighted volunteers
to identify Braille letters or raised Roman letters by touch. As they did so,
the researchers used magnetic pulses to disrupt various regions of their brains.
When they gave pulses to the visual cortex at the back of the head, the blind
subjects felt extra dots or had trouble making out the Roman letters. The same
stimulation had no effect on sighted readers, the team says in this week鈥檚
Nature (vol 389, p 180).
Cohen believes that blind people almost certainly use the visual cortex for
hearing, taste and smell as well. 鈥淭his demonstration takes us one step further
towards explaining the improved sensory abilities of blind people,鈥� he says.
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