Dr. John Mazziotta wants to chart the terrain of the human brain, creating
a map that doctors can use someday in diagnosing illness and perhaps unlocking
the mysteries of thought. Trouble is, there's no compass.
"We're trying to build a representative atlas of the human brain, similar to geography of the Earth," he said in an interview earlier this month. "But, unlike the Earth, there is no agreed-upon navigation system -- no altitude, longitude, latitude."
Mazziotta, a neurologist at the University of California, Los Angeles, heads a $4.5 million national project to map the brain and its workings. Using the latest imaging technology, like MRIs and PET scans, he and fellow researchers hope to eventually illuminate mysteries of thought, movement and the progression of disease.
"These kinds of techniques will allow us to see the earliest manifestations of diseases ... like Alzheimer's disease, Parkinson's disease. In addition it will be extremely helpful in areas where we have less insight -- disorders like autism, dyslexia, schizophrenia, depression," Mazziotta said.
Sometime in the future, doctors will use a combination of gene mapping and brain mapping to determine whether someone has a genetic predisposition to a disease and then monitor the brain regions where changes are anticipated.
However, researchers must first chart the brain, no two specimens of which are alike. The task is daunting; the 3-pound brain "is basically a chemical electrical factory" with 10 billion working parts, Mazziotta said.
A consortium of federal agencies is funding the project with a five-year grant that runs out in 1998. Once researchers nail down the brain's anatomy, they'll move on to map the processes associated with movement, speech, sensation, thought and memory. Then they'll pinpoint the subtle changes in chemistry and function associated with diseases. They'll be linking activity to physiology, Mazziotta said.
Just as cartographers can show smog and rainfall on a topographic map, scientists can layer their image of the brain with such variables as blood flow, abnormalities from disease or injury and the distribution of cell receptors for important chemicals.
The goal is a database for brains spanning all ages, populations and diseases, said Mazziotta, co-director of the UCLA Brain Mapping Division.
Comprising researchers at UCLA, the University of Texas-San Antonio, Montreal Neurologic Institute and in Sydney, Australia, the brain mapping group seeks "to make something we can easily distribute" through the Internet, Mazziotta said.
So far, brains from hundreds of people who donated their bodies to science have been carefully turned into microthin slices of tissue and photographed by digital cameras. The images reveal chemistry as well as cellular and microscopic organization of the brain.
Researchers can use mathematical manipulations to restore the natural shape of slices squashed by cutting. They use a warping technique analogous to the "morphing" process used by moviemakers to seamlessly merge different faces or figures.
The other type of data being used comes from detailed MRI -- Magnetic Resonance Imaging -- scans of living brains, showing sites of brain activity. MRI scanners use magnetic fields and radio pulses to make images.
Eventually, the researchers will incorporate PET scans showing brain activity when research subjects are asked to carry out specific tasks. PET scanners use radio waves to measure how chemicals move through brain tissue. The brain mapping project is part of the larger Human Brain Project, coordinated through the National Institute of Mental Health.
Other Southern California institutions are involved in the brain project. The California Institute of Technology in Pasadena is doing high-field MRI scans of animal brains with an instrument about seven times stronger than those commonly found in hospitals. The Jet Propulsion Laboratory in Pasadena has been working with UCLA on methods of analyzing brain tissue from cadavers and developing "very high-speed computer processing techniques to manage this huge data set," Mazziotta said.
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