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Nation's most powerful brain scanner devoted solely to research inaugurates new era of brain research at UC Berkeley
20 Nov 2000

By Pat McBroom, Media Relations

 See fMRI scans from a recent experiment

  Health Sciences Initiative

Berkeley - The most powerful magnetic resonance imaging (MRI) scanner in the country to be devoted solely to basic research on the brain is being unveiled today (Monday, Nov. 20) at the University of California, Berkeley.

The new $5 million brain imaging center launches an era of extraordinary neuroscience research at UC Berkeley. 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 today 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 UC Berkeley's 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 UC Berkeley Chancellor Robert 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," he said.

Research using the new 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 UC Berkeley's 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 (fMRI), in which neuroscientists detect and display brain activity less than a second long. (See fMRI scans from a recent experiment)

"Mental events last only a few milliseconds," said Mark D'Esposito, M.D., UC Berkeley 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."

The non-invasive procedure carries no risk for the individual undergoing a scan.

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 underway at UC 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. (See fMRI scans from a recent experiment)

D'Esposito, a neurologist and the first of six faculty members to be hired by UC 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 was 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.

"Why these differences in brain activity occur between individuals and age groups, and how this affects their performance, are clearly key questions we have to answer," he said. "This research has only begun."

Other kinds of brain research with the MRI will involve subjects with certain kinds of neurological damage who have participated as volunteers in a wide variety of basic studies on visual perception, motor function, memory, language and attention. This research is being carried out by another neurologist, Robert Knight, M.D., a professor of psychology at UC Berkeley.

Knight, who came to UC Berkeley last year, was the first neurologist in more than a century to be hired by a psychology department anywhere in the nation.

Goodman, the neuroscience institute director, said the campus's acquisition of the new MRI scanner "exemplifies Berkeley's commitment to health science and to integrating basic neuroscience with medical therapy for neurological and psychiatric disorders." Many of the researchers involved in the new brain research are from the Department of Psychology, in the College of Letters & Science.


Related story:

Got the picture?: A magnetic imager with three times the sharpness of standard scanners goes online
(Berkeleyan, 27 Nov)


Health Sciences Initiative

  Below are four fMRI (functional magnetic resonance imaging) brain scans obtained during a visual memory task. The results of the experiment were reported in November 2000 by Mark D'Esposito and Charan Ranganath of the University of California, Berkeley, at the annual meeting of the Society for Neuroscience.

brain scan images

  In scan 1, a subject is asked to remember a face. Areas at the rear of the brain that process visual information are active during this task, as is an area in the frontal lobe.

In scan 2, the subject is asked to "think about this face." Surprisingly, the hippocampus is activated - the first time this has been documented. The hippocampus was already known to be important for memory, but these results show that this part of the brain is specifically active during the time when we are remembering new information.

In scans 3 and 4, the subject was asked to compare another face to the remembered face. Some of the same visual areas are activated as during the initial memory task, but other areas, such as part of the frontal lobe, are involved in making a decision about the memory.

Credit: Mark D'Esposito and Charan Ranganath Department of Psychology & Helen Wills Neuroscience Institute University of California, Berkeley (2000)