In the brains of people blind from birth, structures used in sight are still put to work — but for a very different purpose. Rather than processing visual information, they appear to handle language.
Linguistic processing is a task utterly unrelated to sight, yet the visual cortex performs it well.
“It suggests a kind of plasticity that’s even broader than the kinds observed before,” said Marina Bedny, a cognitive neuroscientist at the Massachusetts Institute of Technology. “It’s a really drastic change. It suggests there isn’t a predetermined function an area can serve. It can take a wide range of possible functions.”
In a study published Tuesday in the Proceedings of the National Academy of Sciences, Bedny’s team monitored the brain activity of five congenitally blind individuals engaged in language-intensive tasks.
Immense neurological plasticity was suggested by research conducted in the late 1990s on “rewired” ferrets — after their optical nerves were severed and rerouted into their auditory cortices, they could still see — but such studies, already ethically troubling in animals, would be unconscionable in humans