Nicotine withdrawal, smoking &amp; attention: an fMRI study
Creators: name: University Of California Office Of The President
Publisher: name: University of California Office of the President
publisherIdentifier: https://ror.org/00dmfq477
publisherIdentifierScheme: ROR
Year: 2024

description: Nicotine dependence is a psychiatric disorder characterized by the regular use of nicotine, usually by smoking. When regular smokers abruptly stop smoking or reduce their use of nicotine, they show withdrawal signs. Many of those who smoke continue to do so to avoid nicotine withdrawal, which includes changes in mood and in the ability to focus attention. Most smokers (80%) express a desire to quit, and 35 percent attempt to do so, but very few are successful, even when they receive treatment in the form of nicotine replacement (e.g., patch or gum) or other pharmacological therapy (bupropion, Zyban®). Laboratory studies of abstinent smokers have shown that the act of smoking or receiving nicotine itself improves performance, especially on tests of focused attention. In some cases, smoking even a single cigarette produced improvement for a person in withdrawal. Such enhancing effects of nicotine (or other components of smoking) may be a reason why individuals continue to smoke. This research aims to provide a better understanding of how abstaining from smoking may affect brain function in dependent smokers, how smoking can influence brain function, and to what extent nicotine itself (compared with other components of smoking) may produce positive effects.
 
 
 
 
 
 
 
 In order to help explain how nicotine withdrawal and smoking affect different parts and circuits of the brain, we will use a brain imaging method called functional magnetic resonance imaging (fMRI). This method maps the activity of the brain “at work”. It visualizes activity throughout the brain when a person performs a task that requires a certain type of function, such as focused attention. We will use fMRI to test how nicotine dependence and smoking influence the pattern of brain activity when a person performs mental tests that require focused attention. We will compare brain activity of smokers while they are deprived of cigarettes (16 hours) or after they have smoked to satiety. Brain scans (fMRI) will identify activated areas while the participants perform tests of focused attention. One is the Stroop Color-Word Interference Task, which requires participants to ignore the meaning (a color) of a written word that is presented while naming the color in which it is actually presented. In a special version of the task, the “Smoking Stroop”, smokers are asked to name the colors of words that are related to smoking and are more distracting to them. These tasks activate specific regions in the prefrontal cortex of the brain, especially the anterior cingulate gyrus. This gyrus is thought to play an important part in a person’s ability to ignore distracting stimuli while focusing attention.
 
 
 
 
 
 
 
 Based on prior work, we predict that abstinent smokers will show different patterns (and intensities) of brain activation when they perform tasks that require focused attention, compared to the pattern after they have smoked as much as they like. Other prior work suggests that smokers will have a slower reaction when they perform the two tasks during smoking abstinence than during satiety. We predict that the Smoking Stroop task will create more interference and cigarette craving than the Classic Stroop and will produce greater differences between abstinence and satiety states in brain activity as well. We expect that cigarette smoking will reverse some of the differences in brain activation and in performance of the tasks during abstinence so that these measures will be closer to those from the same research participants when they are in a state of satiety. We also anticipate that smoking cigarettes that contain nicotine will have a larger effect than smoking cigarettes that do not contain nicotine; that is, we expect that the combination of nicotine and smoking will be more effective than the act of smoking alone in reversing some of the withdrawal-related deficits.
 
 
 
 
 
 This research aims to identify brain regions and circuits important to the effects of smoking and nicotine withdrawal on the ability to focus attention. The results will help explain: (1) how effects of nicotine on focused attention might contribute to dependence, and (2) whether smoking is sustained to avoid cognitive deficits during abstinence. There is a pressing need for improved therapies for nicotine dependence. Although the proposed research cannot identify treatments directly, it will provide a better understanding of the biological basis of nicotine dependence and nicotine withdrawal, and thereby may help in the rational design of new treatments.