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Abstract:
Nicotine withdrawal alters performance on memory tasks. Using
positron emission tomography and H
2
O
15
, regional cerebral blood flow (rCBF) activation was assessed
during a working memory task in nonsmokers (n=6) and in 12 hr
nicotine abstinent smokers (n=6). Each subject participated in two
conditions (administration of 4 mg nicotine gum or matched placebo
gum,15 min prior to scanning) at one week interval. RCBF
activation, but not task performance, differed between groups and
conditions.
In nonsmokers
, rCBF increased in inferior anterior frontal, superior temporal,
and superior parietal gyri during memory task compared to control
task. Nicotine enhanced this activation.
In smokers
in withdrawal, the same areas were activated, but to a lesser
degree. Furthermore, nicotine reduced this activation. These
preliminary findings support an effect of nicotine withdrawal on
neural substrates of working memory which may contribute to the
impaired performance on more complex tasks.
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