A small structure in the front of the brain may be a master
 problem solver according to a study that found it works the
 hardest when the mind is confronted with intelligence tests.

  The study, published Friday in the journal Science, measured
 blood flow rates in the brains of test subjects who were required
 to answer a series of puzzles typical of those in IQ tests.
 
  Dr. John Duncan of the Medical Research Council in Cambridge,
 England, and his co-authors report in Science that the most active
 region of the brain during the tests was the lateral prefrontal
 cortex, a structure in the forebrain just above the eyes. This
 structure is present in both the left and right hemispheres of the
 brain.
 
  When 60 test subjects connected to the scan were asked to
 perform a series of verbal and spatial puzzles, like those found in
 IQ tests, the lateral prefrontal cortex was the area that
 experienced the most blood flow.
 
  Duncan said in the paper that this increased activity occurred
 for both simple general intelligence puzzles, called ``low g'', and
 for more difficult puzzles, called ``high g.'' The same activity
 was found for tests that required verbal skills and for those
 requiring spatial understanding.
 
  The study was designed to test two old and competing theories of
 intelligence. One theory, proposed in 1904, was that there is a
 single, general structure, called the ``g-factor,'' that was the
 master problem solver in the brain. The second theory, proposed in
 1916, proposed that different parts of the brain were recruited to
 solve difficult problems.
 
  Duncan and his colleagues said their findings supported the
 ``g-factor'' theory.

  WASHINGTON (AP) _
 "InfoBeat" 11:27 AM ET 07/21/00
    - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
          
              FURTHER REFERENCES

  GO - "search perceptions" - in SEARCH-ENGINE


file-ID www.perceptions.couk.com/forebrain.txt