Researchers looked at the brain activity of a group of 85 heavy smokers (at least 10 cigarettes a day) using a method called fMRI, or functional magnetic resonance imaging. They found that people who had stronger connections between two regions of the brain -- one involved in reward, the other in controlling impulsive behavior -- were more likely to be successful at giving up smoking, at least for 10 weeks.
"This is the largest study to date where we've attempted to identify neural markers, or predictors, of later success in quitting smoking," said Joseph McClernon, associate professor of psychiatry and behavioral sciences at Duke University, who led the current study. Previous research has told us a lot about how long-term smoking alters the brain
, and what the brain of a nonsmoker looks like.
In the study, published in the journal Neuropsychopharmacology
, researchers did fMRI scanning on participants one month before their quit date. Then on their quit date, participants received nicotine patches and checked in with the researchers over the following 10 weeks about whether they relapsed.
The participants who did not relapse could have a good shot of being out of the woods. "Most of the action relating to beating nicotine addiction takes place within the first month or two," said Jonathan Foulds, professor of public health sciences and psychiatry at Penn State University.
The key difference among the participants who managed not to light up again came down to an area called the insula, a prune-sized section that lies deep in the brain. Those with the most activity in the insula were the ones who went on to successfully quit weeks later.
Although it is unclear what the insula is doing, researchers think it acts like a bridge, connecting the reward region with the behavior control regions. The insula has also been linked to other types of drug addiction such as alcoholism
"It's a frontier area, and one that we are interested in going after in terms of interventions for smoking cessation," McClernon said.
The idea is that doctors could one day try to identify smokers who have poor connectivity in this important insula region. Those who do could benefit from therapies such as neurofeedback or transcranial magnetic stimulation (TMS) to strengthen the connectivity.
Although the effectiveness of these therapies for smoking cessation is still being investigated, the current findings could at least suggest an area of the brain that researchers could target, McClernon said. His group is currently testing whether neurofeedback that involves asking people to recall a time that they successfully resisted a temptation could increase connectivity through the insula.
In addition, people with poor brain connectivity might need more help in quitting smoking, such as possibly giving successful quitters monetary rewards
, McClernon noted.
Another recent study suggested that fMRI could become a routine part of treating conditions
, such as depression. If brain connectivity and the insula region turns out to be the key to quitting smoking, scans could also become part of smoking cessation programs.
For his part, however, Foulds said there is not enough known about TMS or neurofeedback to gauge whether the current findings could help advance those therapies, and that they will probably not be affordable options anyway.