May 12, 1995
Media Contact: Michael Purdy
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"The pieces of the schizophrenia puzzle are starting to come together."
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," says Godfrey Pearlson, M.D., a Hopkins professor of psychiatry. Pearlson and Patrick Barta, M.D., Ph.D., 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 researchers focused 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 schizophrenialike symptoms, strongly suggests that problems in the planum are closely linked to schizophrenia, Pearlson says. "For example, a Japanese group has shown that the planum becomes more active when schizophrenics hear imaginary voices," says Pearlson. "Another group found that a normal person's planum temporale becomes active when they perform certain language tasks, while a schizophrenic's does not."
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," says Pearlson.
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," says Pearlson.
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, says Pearlson.
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.
His research was funded by the National Institute for Mental Health.