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Proc Natl Acad Sci U S A. 2001 Apr 10;98(8):4728-33. Epub 2001 Mar 27.

Effect of nicotine on brain activation during performance of a working memory task.

Author information

1
Brain Imaging Center and Clinical Pharmacology and Therapeutics Branch, National Institute on Drug Abuse, Baltimore, MD 21224, USA. mernst@intra.nida.nih.gov

Abstract

Nicotine influences cognition and behavior, but the mechanisms by which these effects occur are unclear. By using positron emission tomography, we measured cognitive activation (increases in relative regional cerebral blood flow) during a working memory task [2-back task (2BT)] in 11 abstinent smokers and 11 ex-smokers. Assays were performed both after administration of placebo gum and 4-mg nicotine gum. Performance on the 2BT did not differ between groups in either condition, and the pattern of brain activation by the 2BT was consistent with reports in the literature. However, in the placebo condition, activation in ex-smokers predominated in the left hemisphere, whereas in smokers, it occurred in the right hemisphere. When nicotine was administered, activation was reduced in smokers but enhanced in ex-smokers. The lateralization of activation as a function of nicotine dependence suggests that chronic exposure to nicotine or withdrawal from nicotine affects cognitive strategies used to perform the memory task. Furthermore, the lack of enhancement of activation after nicotine administration in smokers likely reflects tolerance.

PMID:
11274349
PMCID:
PMC31902
DOI:
10.1073/pnas.061369098
[Indexed for MEDLINE]
Free PMC Article
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