Nicotine Stroop and addiction memory--an ERP study.

Drug-related cues have been shown to take effects on behavioral performance and physiological parameters such as event-related brain potentials (ERPs). In the present study we obtained EEG data during a modified Stroop task and during a color matching task using smoking related and neutral words (nicotine Stroop) in smokers and non-smoking controls. We assumed that in smokers smoking-related word meanings would interfere with color matching, and that this should be reflected in an ERP activation pattern comparable to that induced by the Stroop task. In smokers and non-smokers the classic Stroop-related interference effect of longer reaction times in the incongruent condition could be observed. This interference effect in both groups was related to a late posterio-central relative negativity and a right frontal relative positivity in the incongruent compared to the congruent condition. The behavioral data in the color matching task (nicotine Stroop) derived from both groups did not show a comparable interference effect related to the use of drug-related words. However, in smokers the smoking-related words elicited ERP activation patterns comparable to those evoked by the Stroop interference task. The ERP results are discussed as possibly reflecting a modulation of color processing of smoking-related words in smokers. The results imply an interference, but also attention enhancing, effect of smoking-related words in smokers, which maybe associated with addiction memory and enhanced sensitivity for drug-cues. Therefore, the addiction memory driven interference effect might be counteracted by performance enhancement induced by the same nicotine cues.