The majority of cessation attempts in nicotine-dependent individuals result in relapse. It is unknown if cessation failure is related to a change in a reward's motivational value (incentive salience), a change in inhibitory ability, or is attributable to other factors. To test for stress effects on incentive salience, and specifically assessing a potential differential effect on immediate versus delayed reward, neuroimaging and behavioral data were collected while 17 overnight-abstinent male cigarette smokers engaged in a reward anticipation task. During the task, which was an adaptation of the monetary incentive delay paradigm (MID; Knutson, Westdorp, Kaiser, & Hommer, 2000), participants attempted to win prizes varying in immediacy (now or in seven days) and type (money or nicotine vapor). When a participant won immediately-available nicotine vapor, he was allowed draw one puff of nicotine vapor before the subsequent trial began. Participants were scanned twice; once after stress induction using the cold pressor task (Lovallo, 1975) and once after a control task. Reward immediacy was associated with faster reaction times (RT) and stronger blood oxygen level-dependent (BOLD) signals in the bilateral insula and anterior cingulate cortices. Under greater stress, however, the immediacy-related anterior cingulate BOLD signal was significantly lower than in the control condition. Furthermore, slower RTs in the stress condition suggested that stress decreases incentive salience of anticipated rewards. These results were unexpected, and may be related to anhedonia associated with acute withdrawal.
|Advisor:||Monterosso, John R.|
|Commitee:||Bechara, Antoine, Kutch, Jason, Saxbe, Darby|
|School:||University of Southern California|
|School Location:||United States -- California|
|Source:||DAI-B 74/10(E), Dissertation Abstracts International|
|Subjects:||Neurosciences, Physiological psychology|
|Keywords:||Addiction, Anhedonia, Reward, Smoking, Stress, Value|
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