Universities vie for tool that shows brains at work
A brain scanner costs a couple of million dollars. It is so complex to run, it needs frequent babying by a physicist. And over the last several years, its power to watch the human mind at work has become so irresistibly seductive that psychology researchers from Cambridge to Berkeley are deciding they simply must have a "magnet."
It is as if, until these brain scanners arrived, psychologists were trying to figure out how a car works just by driving it around, said Nancy Kanwisher, a noted brain imager at the Massachusetts Institute of Technology. "Now, somebody says, `Hey, let's open the hood and look inside!' "
A scanner, formally known as a functional magnetic resonance imaging, or fMRI machine, shows researchers the relative activity of different parts of the brain over time, allowing glimpses of what happens when a person, say, pictures his mother's face or attacks a moral dilemma. Already they are being used in surgery and are leading to new understandings of addiction, complex social behavior and psychiatric disorders.
And despite a scanner's price tag, it appears to be the gotta-have-it tool of the moment for psychologists who once contented themselves with rat mazes and push-buttons.
Harvard is currently talking about getting a scanner or two for its psychology department in William James Hall. Tufts is planning to include a research fMRI in an expanded new neuroscience center. Dartmouth jumped ahead in 2000 by putting one into its new brain building.
The number of published research papers using fMRI has increased exponentially from two in 1990 to 746 in 2001, by one count. Now, an estimated four fMRI papers per day are published in scientific journals.
Increasingly, researchers "are convinced -- or at the very least, their students are convinced -- that you have to have a magnet," said Dr. Bruce Rosen, director of the Athinoula A. Martinos Center for Functional and Structural Biomedical Imaging in Charlestown. The center, shared by Harvard, Massachusetts General Hospital and MIT, is the largest of its kind in the world, with nine research magnets -- but local researchers still want more.
MRI's are long familiar in general medicine as body scanners. But the "functional" variety can pick up blood flow changes in the brain that reflect changing patterns of activity inside.
In shedding new light on how the brain operates, fMRI's also promise to transform the profession of psychology, which has sometimes been derided as a quasi-science based more on touchy-feely talk than hard evidence.
"My bet is that in 100 years, the availability of these neuro-imaging techniques will be seen as the pivotal event that firmly established psychology as a natural science," said Harvard psychology professor Stephen Kosslyn.
In the dozen years that functional MRIs have been in use, they have brought new insights into basic brain functions like vision and language. More and more researchers also have begun using them to try to understand complex behavior like economic choices, and moral reasoning.
One study found that in white students who were not consciously racist, an area associated with fear "lit up" more when they were shown unfamiliar black faces than unfamiliar white faces. Other work is teasing out what happens in the brain during economic decision-making, with the goal of improving economic models. Soon, said John D. Van Horn of Dartmouth's Center for Cognitive Neuroscience, fMRI will model patterns of thought "the way climatologists now do using atmospheric data to visualize the weather." Imaging has already revolutionized research on addiction by showing how addicts' brains differ from those of non-addicts, said Alan Leshner, president of the American Association for the Advancement of Science and former director of the National Institute on Drug Abuse. "You can talk about your brain on drugs forever, but if you can't show it to anybody, why would they believe you?"Some top medical centers use fMRI machines during surgery for brain tumors or epilepsy to pinpoint the important parts of a patient's brain that must be spared. Researchers say imaging is also expected to help improve psychiatric treatment by helping doctors divide broad diagnoses, like depression or schizophrenia, into smaller subcategories, each of which may have a treatment that works best.
Functional MRIs are only one of a handful of powerful imaging techniques, and they are far from perfect. Brain events happen in milliseconds, but the scanners are only capable of measuring blood flow changes, which take seconds.
The machines are also tricky to use, and require high-level computer power to derive and analyze images from the masses of data they take in. Critics also say some conclusions drawn from the data are more conjecture than fact, and that sometimes money spent on scans could be better spent on other research.
The scanners are expensive not only to buy but to run, costing about $500 to $1,000 an hour. But despite the cost and the criticism, General Electric, the market leader in sales of fMRI machines, said sales have climbed 10 to 15 percent per year for each of the last five years.Marcus E. Raichle, an imaging pioneer, reported in the Journal of Neuroscience in May that there are now 58 research-oriented magnet centers worldwide.Some researchers are wondering when scanning will reach a saturation point. But its appeal is hard to beat, said Jody Culham, a brain imaging specialist at the University of Western Ontario.
Sometimes, as she analyzes fMRI data, she says to herself, "Wow, I'm looking at someone's brain at work."
Carey Goldberg can be reached at goldberg@globe.com.
