Brain imaging detects desire


The striking of a match or the nervous patter of addicts preparing for a drug buy are powerful enough images to set off a series of cerebral reactions of desire.

So Anna Rose Childress, Ph.D., grabbed a camcorder and filmed homespun mini-movies of such behavior, showing the tapes to her study subjects and seeing what went on in their brains.

Her results map out some of the most basic elements of desire, demonstrating the flow of blood to "hot spots" in the brain that cause heightened arousal and trigger the urge to use.

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"Once we get a map of what is happening to them, we can develop medications to help blunt that craving," said Anna Rose Childress, Ph.D., of her addiction research patients.

"We're attempting to image what goes on in the brain during that throbbing, pulsating desire for cocaine," said Childress, a clinical associate professor of psychology in psychiatry and Penn's Treatment Research Center.

Her research has been ongoing for the past 15 years, the last five of which she has been able to employ PET scans, which detect minute amounts of radioactivity tracing brain-blood flow. PET scans use a camera that "looks like a big donut" to create three-dimensional images of the brain and its activities.

"Where the brain is working harder, more blood tends to go," Childress said. "The hot spots are the most active and the ones to bet on in award or pleasure association. It's a lot like sexual arousal, only stronger."

The desire for food, sex or substances such as cocaine show similar structures of activity when subjects are in anticipation of any of them, Childress said. The challenge in coming up with anti-craving medication lies in the ability to isolate where the undesirable cravings are focused.

"Once we get a map of what is happening to them, we can develop medications to help blunt that craving," she said. "But, since there's the same hard-wiring for [several cravings], we must find one that's helpful for one, but not all of them.

"Most people wouldn't want to take a drug that would blunt their desire for food or sex," Childress chuckled. "It would be an unwanted side effect."

She calls her findings identifying these regions "an exciting first step" in the research.

"These hot regions, the basis of cravings in the brain --until now, we've only had an inkling of what was going on," Childress said. "It's an exciting time in the research."

The research has begun attracting attention: Childress was featured last week on NBC Nightly News and on WHYY's "Close to Home," a new Bill Moyer PBS series. The five-part series premiered March 29, and examines many of the personal issues surrounding addiction, including Moyers' discussion of his son's battle with drug and alcohol addiction.

In the second segment, "The Hijacked Brain," Childress explains her research about the brain's response to certain drug-related stimuli and her excursion into filmmaking. The important discovery in the brain imaging, she said, is that the "hot spot" sites are only activated by the drug-related videos, not, for example, by other videos, about nature or other subjects. And the patients serving as actors and advisors in the movies enjoy the shoot despite experiencing some of that craving.

"My patients are my best collaborators and consultants," Childress said. Their critiques of the realism are a big help, according to Childress. They especially like getting to be in the mini-movies, she said.

"A lot of them really want to get something back from [participating in] the research," Childress said.

Originally published on April 2, 1998