Campus unveils powerful brain scanner devoted solely to research

By Patricia McBroom, Public Affairs

A computer screen displays brain images taken with the new 4 Tesla imager. Peg Skorpinski photo

29 NOV 2000 | The most powerful magnetic resonance imaging scanner in the country to be devoted solely to basic research on the brain is now in use by campus researchers.

The new $5 million brain imaging center launches an era of extraordinary neuroscience research on campus. It brings together scientists from many disciplines - physics, chemistry, biology, psychology and computer sciences - to study the living brain with this state-of-the-art research tool.

The MRI scanner will be officially launched as part of the Henry H. Wheeler Jr. Brain Imaging Center, where the 14-ton scanner, manufactured by Varian Inc., of Palo Alto, was installed earlier this year. Inauguration of the center moves forward the Health Sciences Initiative, a commitment to deploy the campus's rich intellectual resources across disciplines to solve problems of human disease and unlock the mysteries of the mind.

"We are thrilled to officially welcome this new magnetic imaging scanner and the Henry H. Wheeler Jr. Brain Imaging Center to our campus," said Chancellor Berdahl. "Berkeley is proud to lead a new era of neuroscience research and to continue, through this important part of our Health Science Initiative, to study the brain in an unprecedented way and seek solutions to our most pressing health problems."

Research using the scanner will include studies of both normal and neurologically impaired individuals, as scientists seek to understand the impact of aging on memory and attention, as well as how these functions are disturbed in people with Alzheimer's disease, Parkinson's disease, and attention deficit disorder.

"This is a very special facility, one of the few in the world which is used purely for basic research by neuroscientists, with collaboration from physical and chemical scientists who can push forward the frontiers of technology," said Corey Goodman, who holds the Evan Rauch Chair of Neuroscience and leads the Helen Wills Neuroscience Institute, the parent organization of the Brain Imaging Center.

"We want to integrate the neurosciences from one end to the other, from psychology and behavior to the nuts and bolts of genes and genomes," said Goodman. Roughly three times more powerful than the 1.5 Tesla MRI scanners used for clinical purposes, this research scanner can visualize anatomical detail less than a millimeter in size. The smaller machines can visualize detail only in the range of a few millimeters - a major difference in terms of neural activity.

More importantly, the machine is fast enough to support advanced work with functional MRI, in which neuroscientists detect and display brain activity less than a second long.

"Mental events last only a few milliseconds," said Mark D'Esposito, professor of neuroscience and psychology and director of the new Brain Imaging Center.

"Only in the last few years have we been capable of capturing this level of brain activity, and each year our methods improve," said D'Esposito. "The temporal and spatial resolution provided by this machine will give us a unique view of neural activity as it moves across the brain."

Detection of brain activity by the MRI depends on blood flow throughout the three-pound organ. Theoretically, the flow of oxygen-rich blood corresponds to changes in neural activity. Neurons use the oxygen, resulting in hemoglobin changes that are detected as radio signals by the MRI. As it turns out, deoxygenated hemoglobin has slightly different magnetic properties than oxygenated hemoglobin. Radio signals detected by the MRI can then be analyzed by computer and displayed as colored areas of the brain.

Research already under way at Berkeley, using volunteers, has focused on the brain's frontal lobes, the area just behind the forehead that mediates so-called higher cortical functions such as memory, attention and concentration. This area also provides control of visual, spatial and motor activity.

D'Esposito, a neurologist and the first of six faculty members to be hired by Berkeley's neuroscience institute, has found that, during memory tasks, the frontal lobes function differently in young people (ages 18-25), compared to older people (ages 60-80).

"Clearly, short-term memory declines with age, and we see the corresponding changes in brain activity using MRI," he said. "We can show that the frontal lobes function differently in the two groups during a memory task. Differences in brain activity in the younger and older subjects were limited to one region of the frontal lobes. In this region, older individuals used more of the brain even though they were as accurate as the young during performance of the task.

"This finding suggests that, for older subjects, using more of the brain in memory tasks has beneficial effects," said D'Esposito, adding that there was a great deal of variation in performance within the group.