FIVU : Science News - for the first time we see an attemt in neurophisology of language
- From: AC <agnescherry@xxxxxxxxx>
- Date: Thu, 1 Sep 2011 07:50:41 -0700 (PDT)
The foremer divisionalism by 'structure' top Broka and venicke was
artefact in that that going into the brain and stimulating the
invoking center further and than even cuting it off is marely
congregating energy of the given language function and not the
structural center; moreover assumption that rception in more on left
or right and pronoucing words opposite of it is also wrong
( tehse cruel experiments were done on me; no person yet took
Localizing Language in the Brain: Study Pinpoints Areas of the Brain
Used Exclusively for Language
ScienceDaily (Aug. 30, 2011) — New research from MIT suggests that
there are parts of our brain dedicated to language and only language,
a finding that marks a major advance in the search for brain regions
specialized for sophisticated mental functions.
Functional specificity, as it's known to cognitive scientists, refers
to the idea that discrete parts of the brain handle distinct tasks.
Scientists have long known that functional specificity exists in
certain domains: In the motor system, for example, there is one patch
of neurons that controls the fingers of your left hand, and another
that controls your tongue. But what about more complex functions such
as recognizing faces, using language or doing math? Are there special
brain regions for those activities, or do they use general-purpose
areas that serve whatever task is at hand?
Language, a cognitive skill that is both unique to humans and
universal to all human cultures, "seems like one of the first places
one would look" for this kind of specificity, says Evelina Fedorenko,
a research scientist in MIT's Department of Brain and Cognitive
Sciences and first author of the new study. But data from neuroimaging
-- especially functional magnetic resonance imaging (fMRI), which
measures brain activity associated with cognitive tasks -- has been
frustratingly inconclusive. Though studies have largely converged on
several areas important for language, it's been hard to say whether
those areas are exclusive to language. Many experiments have found
that non-language tasks seemingly activate the same areas: Arithmetic,
working memory and music are some of the most common culprits.
But according to Fedorenko and her co-authors -- Nancy Kanwisher, the
Walter A. Rosenblith Professor of Cognitive Neuroscience, and
undergraduate student Michael Behr -- this apparent overlap may simply
be due to flaws in methodology, i.e., how fMRI data is traditionally
gathered and analyzed. In their new study, published in this week's
Proceedings of the National Academy of Sciences, they used an
innovative technique they've been developing over the past few years;
the new method yielded evidence that there are, in fact, bits of the
brain that do language and nothing else.
Forget the forest, it's all in the trees
fMRI studies of language are typically done by group analysis, meaning
that researchers test 10, 20 or even 50 subjects, then average data
together onto a common brain space to search for regions that are
active across brains.
But Fedorenko says this is not an ideal way to do things, mainly
because the fine-grained anatomical differences between brains can
cause data "smearing," making it look as if one region is active in
two different tasks when in reality, the tasks activate two
neighboring -- but not overlapping -- regions in each individual
By way of analogy, she says, imagine taking pictures of 10 people's
faces and overlaying them, one on top of another, to achieve some sort
of average face. While the resulting image would certainly look like a
face, when you compared it back to the original pictures, it would not
line up perfectly with any of them. That's because there is natural
variation in our features -- the size of our foreheads, the width of
our noses, the distance between our eyes.
It's the same way for brains. "Brains are different in their folding
patterns, and where exactly the different functional areas fall
relative to these patterns," Fedorenko says. "The general layout is
similar, but there isn't fine-grained matching." So, she says,
analyzing data by "aligning brains in some common space … is just
never going to be quite right."
Ideally, then, data would be analyzed for each subject individually;
that is, patterns of activity in one brain would only ever be compared
to patterns of activity from that same brain. To do this, the
researchers spend the first 10 to 15 minutes of each fMRI scan having
their subject do a fairly sophisticated language task while tracking
brain activity. This way, they establish where the language areas lie
in that individual subject, so that later, when the subject performs
other cognitive tasks, they can compare those activation patterns to
the ones elicited by language.
A linguistic game of 'Where's Waldo?'
This methodology is exactly what allows Fedorenko, Behr and Kanwisher
to see if there are areas truly specific to language. After having
their subjects perform the initial language task, which they call a
"functional localizer," they had each one do a subset of seven other
experiments: one on exact arithmetic, two on working memory, three on
cognitive control and one on music, since these are the functions
"most commonly argued to share neural machinery with language,"
Out of the nine regions they analyzed -- four in the left frontal
lobe, including the region known as Broca's area, and five further
back in the left hemisphere -- eight uniquely supported language,
showing no significant activation for any of the seven other tasks.
These findings indicate a "striking degree of functional specificity
for language," as the researchers report in their paper.
Future studies will test the newly identified language areas with even
more non-language tasks to see if their functional specificity holds
up; the researchers also plan to delve deeper into these areas to
discover which particular linguistic jobs each is responsible for.
Fedorenko says the results don't imply that every cognitive function
has its own dedicated piece of cortex; after all, we're able to learn
new skills, so there must be some parts of the brain that are both
high-level and functionally flexible. Still, she says, the results
give hope to researchers looking to draw some distinctions within in
the human cortex: "Brain regions that do related things may be nearby
… [but] it's not just all one big mushy multifunctional thing in
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