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Scientists shift on brain speech centre

2012-01-31 10:30

Washington - The part of the brain used for speech processing is in a different location than originally believed, according to a US study on Monday that researchers said will require a rewrite of medical texts.

Wernicke's area, named after the German neurologist who proposed it in the late 1800s, was long believed to be at the back of the brain's cerebral cortex, behind the auditory cortex which receives sounds.

But a review by scientists at Georgetown University Medical Centre of more than 100 imaging studies has shown it is actually 3cm closer to the front of the brain, and is in front of the auditory cortex, not behind.

"Textbooks will now have to be rewritten," said neuroscience professor Josef Rauschecker, lead author of the study which appears in the Proceedings of the National Academy of Sciences.

"We gave old theories that have long hung a knockout punch."

New insight


Rauschecker and colleagues based their research on 115 previous peer-reviewed studies that investigated speech perception and used brain imaging scans - either MRI (functional magnetic resonance imaging) or PET (positron emission tomography).

An analysis of the brain imaging co-ordinates in those studies pointed to the new location for Wernicke's area, offering new insight for patients suffering from brain damage or stroke.

"If a patient can't speak, or understand speech, we now have a good clue as to where damage has occurred," said Rauschecker.

It also adds an intriguing wrinkle to the origins of language in humans and primates, who have also been shown to process audible speech in the same region of the brain.

"This finding suggests the architecture and processing between the two species is more similar than many people thought."

Lead author Iain DeWitt, a PhD candidate in Georgetown's Interdisciplinary Program in Neuroscience, said the study confirms what others have found since brain imaging began in earnest in the 1990s, though some debate has persisted.

"The majority of imagers, however, were reluctant to overturn a century of prior understanding on account of what was then a relatively new methodology," he said.

"The point of our paper is to force a reconciliation between the data and theory."

Comments
  • Sean - 2012-01-31 11:02

    lol then a hundred years from now another correction

      planetdonovan - 2012-01-31 12:03

      that is the scientific method - to admit fallibility and make constant corrections.

      Ian - 2012-01-31 12:59

      At least science admits it's mistakes, and corrects them. i can think of some other views that react more violently....

      Sean - 2012-01-31 16:42

      yes agreed you guys stated the obvious was just saying science is wrong in some cases so how do you know what is right it might be wrong tomorrow is all I'm saying

      Grant - 2012-01-31 20:15

      //just saying science is wrong in some cases so how do you know what is right it might be wrong tomorrow is all I'm saying// The original position is based on evidence, someone did the work. When more evidence is found it will either substantiate the position or alter it. While some things (like the operation of the brain) are not very well know, this doesn't automatically make everything in science just as transient. It also doesn't give us as lay people the authority to make calls on scientific discoveries. Just saying, comment may be misdirected.

  • ludlowdj - 2012-01-31 13:31

    The problem of course has nothing to do with science admitting its mistakes or rectifying them but rather the scientific community's insistence on declaring something to be a fact and teaching it at as such at school level for years before suddenly finding out they are wrong and rewriting everything. In all to many cases today's "scientific fact" turns out to be tomorrows fairy tale.

      planetdonovan - 2012-01-31 14:39

      what is the alternative? school text books declaring that the flat earth is the center of the universe?

      Mathys - 2012-01-31 19:57

      The word "fact" hasn't meant "absolute truth" for quite a while. These days it means "provisionaly correct" or "most popular explination". And "Donnie", the earth being the center of the universe, while being highly unlikely, has not been "truely disproven" yet. I know "disproving the existence" of something is a logical fallacy, but you really should keep an open mind. Just make sure your mind doesn't fall out.

      Grant - 2012-01-31 20:24

      //The problem of course has nothing to do with science admitting its mistakes or rectifying them// The problem is actually laypeople reaching conclusions based on no evidence whatsoever, where qualified specialists are actualy doing the work. //but rather the scientific community's insistence on declaring something to be a fact and teaching it at as such at school level for years before suddenly finding out they are wrong and rewriting everything.// The brain is still a grey area to science, you can expect our knowledge to shift as technology improves. Concepts like evolution are well proven and are unlikely to change due to the overwhelming level of support for them. Suddenly our knowledge about the brain may shift (note: the article relates the brain speech centre - not the entire brain), your assertion that the scientific community would re-write "everything" is false, it is only our knowledge o the speech centre that has changed. //In all to many cases today's "scientific fact" turns out to be tomorrows fairy tale// Justify your standpoint comparining scientific concepts that have been proven completely false versus discoveries that have at at least had unchanged core concepts? No? Then this is your opinion. Don't try muddy the waters for others because of your personal dissapointment with the scientific community.

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