Effects of Cigarette Smoking on Bilateral Electrodermal Measures of the Orienting Reflex

Bilateral skin conductance was recorded in 6 male and 6 female smokers and in 6 male and 6 female nonsmokers on two different days. On the first day, a 10-min rest period during which 3 male and 3 female smokers smoked a cigarette was followed by a taped series of common and uncommon innocuous tone stimuli to which evoked responses were measured. Nonsmokers did not smoke prior to presentation of the tones. On the second day, one week later, evoked responding was again measured during two further presentations of the tone stimuli after a 10-min rest period during which the remaining smokers smoked a cigarette. During the first presentation, subjects listened to the tones as before. During the second presentation, subjects performed a pedal-press whenever they heard the uncommon tone in the series. Results showed that smoking depressed responding to common and uncommon tones on the first day, but elevated responding to both tones on the second day during the passive listening phase. During the pedal-press task, smoking selectively elevated responding to uncommon tones. Male smokers gave larger responses to uncommon tones in their left than right hands during the pedal-press task, especially after smoking. Results are interpreted in terms of nicotine-induced enhancement of the voluntary orienting reflex possibly mediated by the left frontal cortex.