The N2 ERP component as an index of impaired cognitive control in smokers

Impaired cognitive control has been proposed as a hallmark of nicotine dependence and is thought to arise, in part, from synaptic alterations in anterior cingulate cortex (ACC), a primary component of the dopamine reward pathway. The N2 component of the event-related potential (ERP) appears to index a cognitive control process in paradigms such as the visual go/no-go task. Moreover, as dipole-modeling has suggested that the neural generator of the N2 component can be localized to the ACC, this component may prove useful for investigating impairments of cognitive control in smokers. Given conflicting reports of whether the N2 is reduced in smokers (as compared to non-smoker controls), the current study further examined the suitability of this component as an index for impaired cognitive control in smokers. Smokers and non-smokers performed a visual go/no-go task while electroencephalogram (EEG) was recorded. As predicted, the no-go N2 of smokers was significantly smaller than that of non-smoker controls, while the no-go P3 did not differ between groups. Importantly, behavioral performance (reaction time and accuracy) did not differ between smokers and nonsmokers, which might reflect the low levels of nicotine dependence (assessed by the Fagerstrom test) in our sample. The observed N2 modulation in the absence of behavioral impairments provides evidence for the utility of the N2 component as a sensitive measure of impaired cognitive control in smokers, even in those with low levels of nicotine dependence.