Researchers in the Abramson Cancer Center of the University of Pennsylvania have conducted a new neuroimaging study that shows that cigarette cravings in smokers deprived of nicotine are related with increased activation in specific regions of the brain.
John Detre, MD, associate professor of Neurology at Penn developed
a new method of measuring brain blood flow and used it to show how abstinence from nicotine produces brain activation patterns that relate to urge a person to smoke.
The results make an important contribution to understanding smoking urges, a key risk factor for relapse, at the brain level.
Caryn Lerman, PhD, Director of the Transdisciplinary Tobacco Use Research Center and senior author of the paper, said that cravings are a hallmark of drug dependence, including 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. 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," Lerman said.
The study used MRI arterial spin labeled (ASL) technology. ASL, a non-invasive technique for the measurement of cerebral blood flow (CBF) in the brain, was used to compare resting CBF across two scanning sessions which varied by length of periods of abstinence from smoking.
Fifteen regular smokers were enrolled 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 scan.
The results indicated that abstinence-induced, unprovoked cravings to smoke are associated with increased activation in brain regions important in attention, behavioural control, memory, and reward.
"The craving assessments used in our study predict relapse in smoking cessation treatment. If validated in larger studies, 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," Lerman said.
The study will be published in the December 19, 2007, issue of The Journal of Neuroscience.