Bedny, study leader and an MIT postdoctoral associate in the Department of
Brain and Cognitive Sciences, along with a team of researchers including
Rebecca Saxe, assistant professor of brain and cognitive sciences at MIT, and
Alvaro Pascual-Leone, professor of neurology at Harvard Medical School, have
found that the visual cortex, which is responsible for visual processing, can
also change its function to language
transports input from sensory stimuli, such as the scent of a candle or the
sound of a whistle, to the appropriate region in the brain for analysis. The
smell of the candle is sent to the olfactory cortex, and the sound of the
whistle is sent to the auditory cortex. This process suggests that the brain
follows a genetic blueprint, but recent studies are starting to show otherwise.
example, a study in 1996 showed that people who became blind early in life were
able to understand non-visual functions, like reading Braille. But this only
showed that there was activity in the left visual cortex and
did not show whether this involved "full-fledged language
MIT research team has found that the visual cortex can change its function and
recruit certain parts of itself specifically for language processing, making
those who are born blind capable of understanding language. This contradicts
the traditional idea that language processing can only occur in specialized
areas of the brain specifically programmed for language.
have known for more than a century that Broca's area and Wernicke's area are
two regions in the brain necessary for producing and understanding language. It
was thought that these two areas were specifically mapped out for these
purposes only, and that senses like vision and hearing were
specifically assigned to processing centers in the sensory cortices. But now,
the MIT research team has found that the brain is flexible when assigning
functions to certain areas, and for the first time, evidence is available for
flexibility in language processing.
team researched whether certain regions in the brain in blind people could
allow them to understand word meanings and sentence structure. To do this, they
scanned the blind test subjects using functional magnetic resonance imaging
while giving them a sentence comprehension task. What they found was that the
visual cortex showed the same sensitivity to language comprehension as Broca's
and Wernicke's areas, proving that the visual cortex can change functions from
processing images to processing language.
suggests that the intrinsic function of a brain area is constrained only
loosely, and that experience can have a really big impact on the function of a
piece of brain tissue," said Bedny. "We haven't shown that every
possible part of language can be supported by this part of the brain [the
visual cortex]. It just suggests that a part of the brain can participate in language processing without having
evolved to do so."
question left unanswered through this research is why blind people would need
the visual cortex to participate in language processing when the Broca's and
Wernicke's areas function normally. Bedny theorizes that it may be due to a
redistribution of tasks during development of the brain.
these brain functions are getting parceled out, the visual cortex isn't getting
its typical function, which is to do vision," said Bedny. "And so it
enters this competitive game of who's going to do what. The whole developmental
dynamic has changed."
step in the MIT team's research is to study blind children in order to figure
out when the visual cortex begins processing language during development.
This study was published in Proceedings of the
National Academy of Sciences.
quote: P.S. I suggest that the first person that tries to make this a philosophical/theological discussion gets hit with the ban-hammer. :p