Event-related brain potentials as indicators of smoking cue-reactivity.

OBJECTIVE: Reactivity to smoking cues, shown previously by autonomic and self-report variables, was investigated in smokers and nonsmokers using event-related brain potentials (ERPs).
METHODS: Average ERPs to 20 color pictures of people smoking and 20 neutral pictures depicting nonsmoking themes, randomly mixed with 4 repetitions/stimulus, were measured from 20 light-moderate smokers and 18 nonsmokers, following a stressor. Smoker status and stimulus type effects on ERPs and principal components factor scores (FS) were tested by repeated-measures ANOVAs.
RESULTS: Smokers' N268 showed significant medial and midline smoking cue-reactivity (ERP to smoking-related minus neutral stimuli); while a P300-like, P412, showed significant smoking cue-reactivity over medial and left hemisphere scalp. FS analyses confirmed most of the foregoing. P412 smoking cue-reactivity was correlated with unpleasantness-pleasantness cue-reactivity but not with urge-to-smoke cue-reactivity. Nonsmokers' N268 stimulus differences were not significant, but significant P412 stimulus effects (unconfirmed by FS analyses) were found in central-to-posterior and in left parietal-temporal areas.
CONCLUSIONS: Smokers' N268 is identified with a process detecting stimuli incongruent with tobacco-addicted states; and P412 smoking cue-reactivity is discussed in terms of an automatic, perceptual-categorization system, consistent with Tiffany's drug-use and Johnson's P300 models. Implications of ERP smoking cue-reactivity for study of tobacco and other addictions are discussed.