Individual differences in the effect of smoking on frontal-central distribution of the CNV: Some observations on smokers' control of attentional behaviour

Abstract

A previous investigation of individual differences in cortical activation during smoking reported differential development of vertex CNV ‘O’ and ‘E’ wave components in introverted and extraverted smokers. In the present paper the frontal CNV recorded from 12 extraverted and 12 introverted smokers was analysed under simple and choice foreperiod conditions during sham and real smoking. Smokers were matched for age, sex and neuroticism. Analysis of variance revealed significant group by smoking session effects for the later ‘E’ wave component but not for the early ‘O’ wave component. ‘O’ wave negativity though more prominent in frontal regions particularly in extraverts tended to be more affected by foreperiod conditions than smoking sessions. In general smoking produced an increase in central negativity in extraverts, and a decrease in parietal positivity in introverts. These results challenge the stimulus-related/response-related separation of smoking effects made previously to account for early and late CNV component differences. It is suggested that a distinction of CNV components in terms of input (sensory) and output (motor) aspects may anyway be inappropriate. An attempt is made to relate CNV negativity/positivity topography differences to a motor model of attentional strategies differentially deployed during smoking. Extraverted smoker strategies may aim to relieve boredom, enhance readiness to act and so increase central negativity. Introverts may smoke to inhibit distraction, maintain a complex attentional set, and so these affect parietal positivity. It is further suggested that the pharmacological effects of nicotine are those of a generalized mild stressor which supplement the motor aspects of smoking in inducing more motivated performance. Some further predictions concerning the effect of smoking on cortical activity are discussed.