February 5, 2006
Ideas & Trends
Searching for the Person in the Brain
By BENEDICT CAREY
At this rate, it seems that neuroscientists will soon pinpoint the regions in the brain where mediocre poetry is generated, where high school grudges are lodged, where sarcasm blooms like a red rose.
In the last month alone, researchers working with brain imaging machines have captured the neural trace of schadenfreude and the emotional flare of partisan thinking and whatever happens between the ears of a happily married woman when her husband takes her hand.
As the magnetic resonance imaging machines produce pictures with higher resolution Ã¢Â€Â” and that is happening fast Ã¢Â€Â” hundreds of such studies are being published in scientific journals each month.
Meanwhile, a parallel stream of popularizing books, magazines and newspapers, including this one, are publicizing an ever-enlarging array of the now familiar red, gray and blue graphics of imaged brains, and some of them are making extravagant claims for their significance.
Already, lawyers have used M.R.I. brain images to help reduce criminal sentences, arguing that their clients' actions can partly be explained by the way their brains function, or malfunction. Some researchers say their imaging methods can help detect lies.
And last week CBS picked up a one-hour pilot for a show that revolves around brain surgeons in Los Angeles and could feature as many close-ups of gray matter as of actors.
"The whole reason they were attracted to the idea was the brain itself," said Peter Ocko, the scriptwriter. "The mysteries of the brain are really the star of the show."
In a word, the brain has become a pop star.
But is its glossy, computer-enhanced image a superficial one? What does it really tell us about how we function, what motivates us, who we are? An image with this much charisma surely presents opportunities to re-imagine ourselves in a better light; but what are the hazards inherent in fawning over what are, after all, computer graphics?
Neuroscientists themselves debate these questions constantly, and even agree, if uneasily, on some of the answers. First, it is beyond doubt that brain images reveal real biological activity that is associated with genuine human sensations.
"This is what accounts for the sheer delight, the true amazement people have when they see these images: they show that there is a measurable physical response in the brain to things like being in love," said Dr. Lucy Brown, a neuroscientist at the Albert Einstein School of Medicine in the Bronx. "Everyone thought phenomena like love and jealousy were simply impossible to study, that they were too variable, too individual. They preferred to think of them as magic."
Imaging and other techniques have now parted the curtain. The lozenge-shaped amygdala is central to the experience of fear. The delicate-looking horseshoe-shaped area called the hippocampus is crucial to the forging of memories. The visual areas are in the back of the brain.
There is even evidence that people have "grandmother neurons" Ã¢Â€Â” single cells that recognize a unique face. In once recent paper, Dr. Itzhak Fried, a neurosurgeon at the University of California, Los Angeles, and Dr. Christof Koch, a neuroscientist at the California Institute of Technology, reported that a single cell in the hippocampus of a patient being prepared for epilepsy surgery fired vigorously and consistently in response to a picture of the actress Jennifer Aniston, but far less so when the patient looked at other photographs.
Understanding that the shiver of celebrity recognition, or the whole-body ache of longing, leaves a physical trace in the brain seems to give people more sympathy for others' emotions and reactions, say neuroscientists who have presented findings in front of professional and lay audiences.
"Suppose you know someone who's having trouble, who's suffering from bipolar disorder or depression, and nothing has helped, no therapy, nothing," said Dr. Brian Wandell, a psychologist at Stanford University who studies the visual cortex. "It's nice to know from this new science that there may be some other way to alter the system" than treating it like a character flaw.
The catch is that, for all their power, imaging machines are like the Mars probe: they see surfaces, mountain peaks, valleys Ã¢Â€Â” without being able to take samples of the underlying terrain.
The regions that peak in activity when a person is happy or guilty or jealous are connected to many other areas along complex circuits distributed throughout the brain that are, for the most part, still unlit by the computerized spotlight of the imaging machine.
And it is here, in these subterranean, subtle enfoldings of the brain, that neuroscientists say they are most likely to discover its deepest secrets.
"Any new method in neuroscience is powerful in terms of evolution of the field only insofar as it tells us that something we thought we knew is wrong," said Dr. J. Anthony Movshon, director of New York University's Center for Neural Science. So far, he said, brain imaging has not done that.
The technology, he said, though now central to brain science, "is in one sense disappointing, in that so far it has told us nothing more than what a neurologist of the 19th century could have told you about brain functions and where they're localized."
And that may be where the hazard lies. The brain's increasingly popular image is a fascinating prop, a colorful as well as useful map, but so far it provides only the illusion of depth.
The subtle biology that integrates and coordinates disparate areas of the brain, like the visual, the verbal and the emotional Ã¢Â€Â” the interlocking symphonies of activity that make us individuals, that help determine what we do when jealous or inspired by a work of art Ã¢Â€Â” are absent, despite all the color-coding and exotic names for areas of the brain.
"The risk is that seeing the neural activity allows people to take away or excuse responsibility for a behavior Ã¢Â€Â” to take away the individual person," said Dr. Brown of the Einstein School of Medicine.
But she could not elaborate. A camera crew from CNN was due to arrive, to talk to her about the brain in love.