The broad objective of this proposal is to identify functional neuroanatomical correlates of
impairments in decision making and response inhibition during smoking abstinence. We will
measure changes in performance and regional blood oxygenation levels using fMRI while
smokers and non-smokers complete tasks designed to assess decision making and response
Our primary hypothesis is that smoking abstinence will result in impaired decision making
and response inhibition accompanied by decreases in blood-oxygenation-level-dependent (BOLD)
fMRI signal in brain regions associated with these cognitive processes including frontal
cortex and the ventral striatum. Abstinence may also result in performance-related increases
in activation in brain regions associated with effortful processing including the anterior
cingulate cortex in effort to compensate for deficits in other regions. We also hypothesize
that smokers with a history of diagnosis of ADHD will exhibit greater decreases in brain
activity following smoking abstinence. Finally, we hypothesize that smokers during in the
satiated state will exhibit brain activity more similar to that of non-smokers.
- Smoker subjects must have smoked an average of 10 cigarettes per day for two
continuous years of a brand that delivers (by Federal Trade Commission rated yields)
at least 0.5 mg nicotine, have an expired air carbon monoxide reading of at least 10
ppm. Non-smoker subjects must have smoked less than 50 cigarettes in their lifetime,
have not smoked in the last six months, and have an expired air carbon monoxide
reading of less than or equal to 5 ppm. Subjects must be in general good health.
Participants with controlled medical conditions (e.g., hypertension) will be
considered if treatment is not thought to interfere with fMRI measures or potentially
ameliorate smoking withdrawal symptoms.
- Individuals with a major medical condition that would make participation unsafe
(e.g., have pacemaker or other metallic implant), uncomfortable (e.g., chronic pain),
confound results (e.g., psychiatric condition other than ADHD (non-medicated))
suffering from claustrophobia; abnormally afraid of closed-in places will be excluded
from participation. Current alcohol or drug abuse, smokeless tobacco use, or use of
nicotine replacement therapy or other smoking cessation treatment will also be a
basis for exclusion.