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[evol-psych] Scientists Capture Images Of Brain In Action As It's Learning

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  • Ian Pitchford
    Baycrest Center For Geriatric Care http://www.baycrest.org/ 7/1/99Scientists Capture Images Of Brain In Action As It s LearningScientists in Toronto have
    Message 1 of 1 , Jul 1, 1999
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      Baycrest Center For Geriatric Care http://www.baycrest.org/
      7/1/99

      Scientists Capture Images Of Brain In Action As It's Learning

      Scientists in Toronto have captured images of the brain in action as it's
      learning -- an exciting finding that could help in the diagnosis and treatment
      of brain injuries.

      Remember the comic strip analogy of a lightbulb coming on in the brain to
      depict a person who learns and becomes aware of something? It's really a
      "pattern of lightbulbs" according to a study conducted by the Rotman Research
      Institute at Baycrest Centre for Geriatric Care.

      The study, published in the May 28th issue of the international journal SCIENCE
      has generated quite a buzz among neuroscientists and is being billed as a
      significant contribution to understanding how the brain works when conscious
      learning is taking place.

      Scientists already know that 'learning' and 'awareness' is a function of the
      prefrontal cortex of the brain, part of the higher thinking region. Now the
      Rotman study has confirmed that it's actually several regions acting in
      concert.

      "We found that learning and awareness involves a cohesive network of brain
      activity," says Rotman scientist Dr. Randy McIntosh, who led the study using
      brain imaging technology along with co-investigators Drs. Natasha Rajah and
      Nancy Lobaugh.

      "It's like a pattern of lightbulbs coming on. Most of the action is happening
      in the left prefrontal cortex, but we confirmed that areas far away from the
      frontal regions are activated as well. They include the sensory regions that
      provide the visual and auditory information needed to do the task."

      In the study, 12 university students participated in an associative learning
      exercise on a computer. They would hear two different tones and only six in the
      group became 'aware' that one of the two tones always predicted a visual event
      on the computer screen.

      During the exercise, regional cerebral blood flow (which signifies brain
      activity) was measured in both the aware and unaware groups using a brain
      imaging technique called positron emission tomography (PET).

      In students who figured out or became aware that a specific tone predicted a
      visual event, the PET scans revealed activity changes in the prefrontal cortex
      and increased interaction with sensory areas -- indicating a network of brain
      activation. As they learned, these students started to perform the task faster.
      In the unaware group, there was no change in blood flow activity in the
      prefrontal cortex or indication of a larger system of activity, and also no
      improvement in their reaction times.

      "This study actually catches the brain in the act of becoming aware and
      learning," says Dr. Sandra Black, Head of Neurology and Senior Scientist in the
      Aging Research Program at Sunnybrook and Women's College Health Sciences
      Centre.

      "For those people who saw the light, that is who figured out that there was an
      association between the tone and visual image, you could see their brain
      activity changing. It's not just one brain centre where the lightbulb is coming
      on, but different regions turning on like a symphony of fireworks."

      The Rotman study could have broad implications for the diagnosis and
      rehabilitation of brain injuries, says Dr. Black, who is also a senior
      scientist at the Rotman Research Institute.

      "In certain kinds of head injuries, doctors can use this brain imaging
      technique to determine if awareness and learning is happening. Findings from
      this study could also help in the development of new therapeutic strategies for
      associative learning in brain injured people."

      Baycrest Centre for Geriatric Care is an academic centre fully affiliated with
      University of Toronto. Funding for the study was provided by the Medical
      Research Council of Canada, and Natural Sciences and Engineering Research
      Council.




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