Using a novel method of measuring brain blood flow developed by John Detre, M.D., associate professor of neurology at Penn, this study is the first to show how abstinence from nicotine produces brain-activation patterns that relate to urges to smoke.
The findings, published in the Dec. 19 issue of The Journal of Neuroscience, make an important contribution to understanding smoking urges -- a key risk factor for relapse -- at the brain level.
According to Caryn Lerman, Ph.D., director of the Transdisciplinary Tobacco-Use Research Center and senior author of the paper, and colleagues Detre and Ze Wang, Ph.D., cravings are a hallmark of drug dependence, including that of nicotine dependence.
"There have been several brain-imaging studies showing how subjects respond to visual, smoking-related cues, such as a picture of a cigarette or of someone smoking," explained Lerman. "However, less is known about the neural basis of urges that arise naturally as a result of nicotine deprivation.
"This study was designed help fill this research gap."
This combined effort between Penn's Transdisciplinary Tobacco-Use Research Center and the Center for Functional Neuroimaging used MRI arterial-spin-labeled technology
Fifteen regular smokers were included in the study. Each participant was scanned in a resting state on two separate occasions: Participants smoked a cigarette within an hour of the one scan and abstained from smoking overnight for the other.
The findings indicate that abstinence-induced, unprovoked cravings to smoke are associated with increased activation in brain regions important in attention, behavioral control, memory and reward.
Lerman said that "the craving assessments used in our study predict relapse in smoking-cessation treatment."
"If validated in larger studies," she attested, "these results may have important clinical implications. For example, perfusion MRI may aid in the identification of smokers at increased risk for relapse who may require more intensive therapy."