'Virtual' Model Links Language, Schizophrenia

'The pieces of the puzzle 
are starting to come together'


Michael Purdy
-------------------------------
JHMI Public Affairs

     Using computers to dissect "virtual" models of patient
brains, researchers at Johns Hopkins have found an unusual
structural distortion in a language-skills area that is strongly
linked to schizophrenia.

     Aided by the finding, scientists are starting to assemble a
new theory of what goes wrong in the brains of schizophrenics,
and what may help prevent or treat the symptoms.

     "The pieces of the schizophrenia puzzle are starting to come
together," said Godfrey Pearlson, a Hopkins professor of
psychiatry. Pearlson and Patrick Barta, a Hopkins associate
professor of psychiatry, published their new findings in this
month's issue of the American Journal of Psychiatry.

     Schizophrenia affects one in every 100 persons worldwide.
Symptoms can include hallucinations; disordered thoughts,
including forms of aphasia (speech made up of recognizable words
strung together in a nonsensical way); delusions; reclusiveness;
and "flat" emotions.

     Pearlson and his colleagues used magnetic resonance imaging
and other imaging techniques to generate and dissect detailed
"virtual" models of the brains of 14 schizophrenic patients and
14 normal volunteers.

     Because a primary symptom of schizophrenia is speech
disturbance, the focus was on the planum temporale, an area of
the brain known to be involved in language skills.  

     The planum temporale consists of paired areas, one on the
left side of the brain and one on the right. In people who are
right-handed, the left side is normally larger than the right, as
it was in 12 of the 14 normal volunteers in the Hopkins study. 
However, in 13 of 14 schizophrenics, all right-handed,
researchers found the opposite:  the planum was larger on the
right.

     The new finding, combined with earlier research linking the
planum with language skills and schizophrenia-like symptoms,
strongly suggests that problems in the planum are closely linked
to schizophrenia, Pearlson said.

     "For example, a Japanese group has shown that the planum
becomes more active when schizophrenics hear imaginary voices,"
Pearlson said. "Another group found that a normal person's planum
temporale becomes active when they perform certain language
tasks, while a schizophrenic's doesn't" 

     A persistent puzzle is why, if variances in brain structure
normally begin well before birth, schizophrenic symptoms do not
typically emerge until 15 to 20 years later.

     "The answer may be that the brain isn't making full use of
the planum temporale until that point in life, and other brain
areas can make up for the deficit until development does bring
the planum fully on-line," Pearlson said.

     If scientists can determine which areas of the brain are
"making up" for problems in the planum, they may be able to use
this information to develop new therapies for schizophrenia.

     "We might conceivably be able to give patients 'mental
exercises' that would help them develop the areas of their brain
that can take up the slack for the planum," Pearlson said.

     When scientists learn more about the genetic factors that
cause schizophrenia, and how these factors control the
development of the brain's structure, they may eventually be able
to apply genetic therapy or drugs to help prevent schizophrenia,
he said.

     Pearlson and his collaborators plan to explore the function
of the planum and other brain areas like it that may be involved
in schizophrenia, and to work with other Hopkins researchers
involved in the search for genes that cause or promote
schizophrenia. 

     The research was funded by the National Institute for Mental
Health.