Probing How Cigarette Users Respond to Rewards in the Lab and Daily Life
In our previous work, we found that receiving a reward (specifically, winning money) was associated with a weaker response in a brain area called the striatum in cigarette users who anticipated having a chance to smoke soon than in cigarette users who anticipated having to wait several hours before being able to smoke. There is strong evidence that responses in the striatum provide an index of the relative value of reward-related stimuli. That is, larger and/or more preferred rewards evoke stronger responses in the striatum, and vice versa. Thus, one interpretation of our initial findings is that monetary gains were “less rewarding” for cigarette users who expected a chance to smoke soon, relative to those who did not expect to smoke in the near future. In other words, simply perceiving that they will have access to cigarettes in the near future appears to blunt the sensitivity of reward-related brain areas in those who smoke, at least when it comes to “non-drug” rewards like money. In other work, we have found that this change in brain reward sensitivity predicts clinically relevant behavior in the laboratory. Specifically, cigarette users showing the biggest decrease in the neural response to non-drug rewards when anticipating a chance to smoke were those least likely to delay the chance to smoke in order to earn additional money. Thus, we believe that the effect of smoking expectancy on reward sensitivity may play an important role in smoking relapse. One reason why cigarette users abandon quit attempts may be because alternative, non-drug sources of reinforcement (e.g., the prospect of saving money and improving health) seem less appealing in the face of an opportunity to smoke in the near future.
To build on the work mentioned above, we completed a project funded by the National Institute on Drug Abuse (R01DA041438) that was designed to address two key questions about the effects of smoking expectancy on the sensitivity to non-drug rewards. First, does the perception that cigarettes will soon be available dampen incentive processing during the anticipation of potential non-drug rewards, the hedonic responses to reward delivery or both? Second, does the effect of perceived smoking opportunity on reward sensitivity extend beyond the lab to the “real world?” In order to tackle these questions, we combined the unique and complementary strengths of functional magnetic resonance imaging and ecological momentary assessment methods, which will allowed us to gather rich information about precisely how smoking expectancy alters responses to rewards in the brain and in daily life. We are currently in the process of analyzing the data we collected in the project, and presentations and publications will be forthcoming soon!
