Nicotine, like several other drugs of abuse, acts on the brain reward
system. Altered function of this mesocorticolimbic system has been
associated with the transition from controlled drug intake to a compulsive,
uncontrolled drug consumption characterizing addictive behaviour. In
dependent smokers cues associated with smoking can elicit an increased urge
for the drug which seems to be enhanced during phases of nicotine
withdrawal. In contrast, the motivational value of non-substance related
motivational stimuli (e.g. monetary reward) has shown to decrease during
nicotine abstinence. Taken these findings in account, we propose a
motivational dissociation during nicotine withdrawal. The motivational value
of substance-related stimuli (e.g. smoking cues) should be enhanced whereas
the motivational value of non-substance related stimuli (e.g. erotic
stimuli) should be reduced. Such a motivational dissociation could explain
why attempts to quit smoking often fail due to relapse within the first days
of abstinence.
By presenting smoking cues, neutral stimuli, negative stimuli and
non-substance related motivational stimuli (erotic stimuli) during the fMRI
scan components of the reward system (prefrontal cortex, striatum, amygdala)
are activated. Scanning smokers before and after abstinence from nicotine as
well as nonsmoking controls allows us to investigate functional changes in
the reward system during nicotine withdrawal.
Assistent: Mira Bühler
The study is supported by the DFG (SM 80/1-1) |
