Brain-Imaging Tools
Zero in on Schizophrenia

(December 3, 2003) -- Using sophisticated imaging technology that peers deeper into the brain than ever before, scientists reported Tuesday in Chicago that they are beginning to see where schizophrenia begins and possibly what's causing it.

HealthyPlace.com Video Development of Schizophrenia in Brain listen with windows media player

The report highlights the speed of discoveries coming from the new field of brain imaging that scientists say is helping them understand mental disorders such as schizophrenia, dyslexia and antisocial behavior.

"We use a new technique that allows you to peel off the first layer of the brain and look inside," said Manzar Ashtari, associate professor of radiology and psychiatry at Albert Einstein College of Medicine in New York City. "You take all that structure away and see how things are connected."

Showing images of adolescents newly diagnosed with schizophrenia, Ashtari on Tuesday presented the first evidence linking the disorder in youngsters to defective myelination, the white matter that insulates brain cells and allows them to communicate. She presented her findings at the annual meeting of the Radiological Society of North America in McCormick Place.

Ashtari and Dr. Sanjiv Kumara, assistant professor of psychiatry, use a souped-up MRI imaging device known as diffusion tensor imaging to look at the brain's white matter, which had previously eluded studies in living patients.

They found that a switching box in the brain called Heschl's gyrus was defective because of insufficient myelination. Normally the switch box transfers incoming sounds to the brain's command center, the frontal cortex, for interpretation.

Some of the most common symptoms of schizophrenia -- hearing voices and other auditory hallucinations -- may result from a defective switch box that doesn't send messages to the command center, the scientists said. The disorder affects between 1 and 2 percent of Americans.

"There's a pathway that's connecting the gyrus to the frontal cortex that puts all this information together," Kumara said. "If there's some problem with that pathway and there's not efficient transfer of communication of information, then you can sort of see how somebody might get confused and not understand if this is a voice inside of my head or is this a voice outside of my head."

The study involved 20 adolescents with schizophrenia. Diagnosis is made if they meet two or more of five criteria--hallucinations, delusions, thought disorder, bizarre behavior and negative symptoms, such as lack of motivation or loss of enjoyment in activities. Their brain scans were compared to those of 17 normal adolescents.

DTI is one of about five imaging techniques that are enabling scientists to study the way the brain functions under various circumstances, how it is physically constructed, and its chemical makeup at the time thoughts are being constructed.

"We're gaining an enormous new body of knowledge on brain factors which predispose to all sorts of clinical disorders," said neuroscientist Adrian Raine of the University of Southern California. "We have new vistas today which were almost undreamt of before.

"In my field we're really beginning for the first time to literally look inside the brains of murderers and violent offenders in ways that we never could have done before."

advertisement

In Raine's MRI study of psychopaths, he found that they have a significant abnormality in the structure and function of their corpus callosum--the cable of fibers that allows the left and right sides of the brain to communicate and process emotions, attention and arousal--which may put them on the path of violence.

"They're emotionless, cold, blunted and are socially disconnected," he said. "We found that the faulty wiring in the corpus callosum of psychopaths is involved in shaping these classic deficits."

Ashtari said that her findings were similar to those found in adults except that adults have more areas of the brain that appear to lack adequate myelination. That may mean schizophrenia starts off in one area and then spreads to other areas as a person gets older, she said.

The next step is to study younger children who may be at risk for schizophrenia to look for early gyrus changes that might be used as a diagnostic tool before full-blown symptoms develop, Ashtari said. Her work is supported by the National Institute of Mental Health and the National Alliance for Research on Schizophrenia and Depression.

If further studies confirm that a lack of myelination is involved in schizophrenia, then it may be possible to develop drugs that stimulate white matter growth, Ashtari said.

It may also be possible that certain nutritional deficiencies may contribute to the myelination defect and that special diets might be able to prevent it, she said.

In another brain-imaging report presented at the RSNA meeting, neuroradiologist Dr. Jonathan H. Burdette of Wake Forest University found a characteristic abnormality in the brains of people with dyslexia, which affects an estimated 1 in 10 Americans.

Functional MRI studies showed that an area of the brain called the temporoparietal region fails to light up properly when dyslexics are given tests to match letters with their corresponding sound. The job of the temporoparietal region is to match words and sounds.

Further research may lead to screening techniques to detect children before they develop language problems, Burdette said.

Source: Chicago Tribune

top ~ next ~ articles table of contents ~ send page to a friend

We subscribe to the HONcode principles. Verify here.