Brain imaging zones in on vulnerabilities to addiction

Numerous studies have found decreased brain activity in addicted persons compared with healthy individuals in psychological tests, but it was never clear whether the differences might be based simply on impaired ability or lack of motivation. Research conducted at the Brookhaven National Laboratory and published last month broke new ground in suggesting that even in groups of addicts and non-addicts who perform equally well on tests, differences in brain activity can be seen in regions governing behavior and emotion—and therefore drug use.

Published online by the Proceedings of the National Academy of Sciences, the research from the U.S. Department of Energy laboratory offers new clues on the brain regions that could be targeted for new behavioral and pharmacological treatments. This study used functional magnetic resonance imaging (fMRI) to evaluate the amount of oxygen used by specific brain regions during the tests administered to subjects.

“Whether these brain differences are an underlying cause or a consequence of addiction, the brain regions involved should be considered targets for new kinds of treatments aimed at improving function and self-regulatory control,” says Rita Goldstein, PhD, a Brookhaven Lab psychologist and the study’s lead author.

Specifically, the study of 17 cocaine users and 17 healthy individuals measured brain activity during a button-press test in which subjects were rewarded for fast and accurate responses. The fMRI screening showed that the cocaine users had reduced activity in two different portions of the anterior cingulate cortex; one area is related to the monitoring of behavior and the other to the suppression of emotional feelings. Also, researchers found that the functions in these two regions were interconnected in the healthy study participants but not in the cocaine users.

“This work gives us some clues as to what happens when drug users are unable to suppress craving—and how that might work together with an decreased ability to monitor behavior, even during neutral, non-emotional situations, to make some people more vulnerable to taking drugs,” Goldstein said.