Electrophysiological evidence of nicotine's distracter-filtering properties in non-smokers.

Nicotine-enhanced attentional functions are purported to underlie improvements in behavioral performance in cognitive tasks but it is unclear as to whether these effects involve selective attention or attentional control under conditions of distraction. Behavioral and event-related potential measures were used to examine the effects of nicotine on distractibility in 21 non-smokers who were instructed to ignore task-irrelevant auditory stimuli while they performed a visual discrimination task. In a randomized, double-blind, placebo-controlled cross-over design, nicotine gum (6 mg) shortened overall reaction times but failed to prevent increased response slowing and errors caused by deviant sounds. Relative to placebo, nicotine did not modulate the early pre-attentive detection of deviants as reflected in the mismatch negativity but it attenuated the amplitude of the deviant-elicited P3a, an event-related potential component indexing the involuntary shifting of attention. Nicotine also enhanced attentional re-focusing back on to task-relevant stimuli following distraction as evidenced by an increased amplitude of the re-orienting negativity. These findings and the behavioral-electrophysiological dissociation seen with nicotine are discussed in relation to theories of attention and smoking motivation.

Effects of acute nicotine on event-related potential and performance indices of auditory distraction in nonsmokers.

INTRODUCTION: Although nicotine has been purported to enhance attentional processes, this has been evidenced mostly in tasks of sustained attention, and its effects on selective attention and attentional control under conditions of distraction are less convincing. METHODS: This study investigated the effects of nicotine on distractibility in 21 (11 males) nonsmokers with event-related potentials (ERPs) and behavioral performance measures extracted from an auditory discrimination task requiring a choice reaction time response to short- and long-duration tones, with and without imbedded deviants. Administered in a randomized, double-blind, placebo-controlled crossover design, nicotine gum (6 mg) failed to counter deviant-elicited behavioral distraction characterized by longer reaction times and increased response errors. RESULTS: Of the deviant-elicited ERP components, nicotine did not alter the P3a-indexed attentional switching to the deviant, but in females, it tended to diminish the automatic processing of the deviant as shown by a smaller mismatch negativity component, and it attenuated attentional reorienting following deviant-elicited distraction, as reflected by a reduced reorienting negativity ERP component. DISCUSSION: Results are discussed in relation to attentional models of nicotine and with respect to future research directions.