Tobacco smoking, personality and sex factors in auditory vigilance performance

Nicotine pharmacodynamics: some unresolved issues

This paper focuses on some issues in the field of nicotine pharmacodynamics in which widely held suppositions have outstripped the supporting evidence. It considers how far the view that nicotine acts as a stimulant in low doses and as a sedative in higher doses is supported by the data and concludes that within the range of doses ingested by cigarette smokers, only stimulant actions have been reliably observed. It examines evidence for the view that nicotine improves ability to sustain attention and concludes that a positive effect of nicotine not attributable to relief of a withdrawal deficit has yet to be demonstrated. Finally, it considers the issue of physiological tolerance and argues that ideas concerning a role for chronic tolerance in nicotine dependence have yet to be supported empirically. Despite advances in our understanding of nicotine's effects in recent years there is still much work to be carried out before fundamental issues underlying its addictive potential can be resolved.

Effects of tobacco deprivation on alcohol cue reactivity and drinking among young adults

Nicotine and alcohol may have common neurobiological mechanisms of reinforcement. Therefore, withholding one substance might result in compensatory increases in self-administration of the other. This laboratory study investigated the effects of brief tobacco deprivation on alcohol cue-elicited urges to drink, corresponding psychophysiological reactions, and alcohol consumption. Young adults (N=78) who were moderate to heavy smokers and drinkers were stratified and randomized to a 2 x 2 design. Participants were either deprived of tobacco for 5 h or not deprived and then exposed to in vivo alcohol or control beverage cues. Subsequently, participants engaged in a taste-rating task as an unobtrusive measure of alcohol consumption. Tobacco deprivation resulted in increased urge to smoke and decreased cardiovascular responses but did not increase alcohol urges or alcohol consumption. Results indicate that brief tobacco deprivation does not result in compensatory increases in alcohol consumption among young moderate to heavy drinkers.

Effects of tobacco smoking on human ocular smooth pursuit

OBJECTIVE

Test the hypothesis that nicotine-induced nystagmus results in reduced ocular smooth performance and pupil diameter in tobacco smokers.

METHODS

Twenty nonsmokers (age range, 20 to 45 years; mean age +/- SE, 31.5 +/- 1.7 years) and 14 smokers (age range, 17 to 50 years; mean age +/- SE, 30.6 +/- 2.6 years) were studied after a minimum of 2 hours of tobacco abstinence. Subjects were studied before and immediately after they inhaled air through a sham cigarette or after they smoked one of their preferred brand of cigarettes, respectively.

RESULTS

A very small, consistent, and statistically significant increase in smooth pursuit was found with both eyes to a 15 degrees per second moving target after one tobacco cigarette was smoked. This was due to improvement in left and not right eye smooth pursuit. The nonsmokers had no significant change in 15 degrees per second pursuit after sham smoking. Nonsmokers and smokers did not differ in left eye 6 degrees per second smooth pursuit before or after sham or tobacco smoking. The changes in right eye 6 degrees per second smooth pursuit were inconsistent and differed at various times between the two groups. During the smooth pursuit task the pupil diameter of the nonsmokers increased, but there was no change in the tobacco smokers. Black subjects had smaller baseline pupils than white subjects, unrelated to smoking status.

CONCLUSIONS

Contrary to the hypothesis, tobacco smokers had a very small but significant improvement in left eye pursuit but no change in pupil diameter. Race-related differences in baseline pupil diameter were similar in both nonsmokers and smokers.

Smoking and attention: a review and reformulation of the stimulus-filter hypothesis

An accumulation of evidence suggests that smoking may be reinforcing, in part, due to nicotine's capacity to enhance attentional processing. Correspondingly, the stimulus-filter model of nicotine reinforcement asserts that nicotine facilitates cognitive performance by acting as a stimulus-barrier, thereby screening irrelevant and annoying stimuli from the smoker's awareness. A review of the available data suggests that while nicotine does appear to reliably enhance sustained, divided, and focused attention, the stimulus-filter model falls short of adequately explaining the findings. An alternative, attention, allocation model of nicotine reinforcement is reviewed, the tenets of which suggest that nicotine differentially augments attentional processing via its propensity to: (a) induce attentional narrowing, and (b) increase perceptual processing capacity. The motivational implications of the model, including smokers' use of nicotine to dampen stress, are discussed.

Stimulant drugs and vigilance performance: a review

The literature on the effects of some stimulant drugs (amphetamine, methylphenidate, caffeine, and nicotine) on vigilance performance is reviewed. Improvement of overall level of performance (both accuracy and speed) after the intake of amphetamine, caffeine, and nicotine has often been reported, and the decrement in performance with time has been shown to be prevented especially with amphetamine and nicotine. Effects on false alarms are negligible. In studies where a test battery was employed, vigilance tasks appeared to be the most sensitive performance tests in detecting the effects of stimulants; however, different vigilance tasks may measure different aspects of mental functions. There is no support for earlier conclusions that improvements are noticed only in fatigued subjects in protracted sessions. Evidence from several studies does not support the hypothesis that improvements are only a recovery of withdrawal-induced impairment. Because positive effects have been obtained with drugs possessing different mechanisms of action, there is as yet no clear support for a noradrenergic, dopaminergic, or cholinergic theory of sustained attention. Simple neurotransmitter theories of attention and information processing may be untenable.

Acute effects of tobacco on human brain stem evoked potentials

Reports of tobacco-induced electrocortical activation have frequently indicated that this effect is mediated via nicotine's action on sub-cortical structures. This study focused on human brain stem involvement by examining the acute effects of tobacco smoking on brain stem auditory potentials (BSAEPs). Twelve regular smokers were tested on two separate sessions involving sham or real smoking. On each session, BSAEPs were recorded during a baseline period and immediately after smoking. BSAEPs, recorded from Cz, were elicited by presentation of 1,000 monaural, rare fraction click stimuli. Latency and amplitudes of peak components I, III and V were assessed and analysed. No significant effects were observed for latency measures or for amplitudes of peaks I and III. A significant effect was observed for peak V with tobacco resulting in larger amplitudes relative to sham smoking. Peak V reflects activity from upper pontine-lower midbrain sites and this tobacco-peak V finding is discussed in relation to arousal and information processing theories of smoking.

A preliminary study on pain perception and tobacco smoking

Ischaemic pain onset and tolerance in response to a pneumatic blood pressure cuff were compared in 17 non-deprived smokers, 30 deprived smokers, 15 smokers chewing nicotine gum and 16 non-smokers. Following removal of the cuff, all subjects completed the McGill pain questionnaire, rating pain in terms of its sensory, affective, evaluative and miscellaneous qualities. Group differences were found in the time elapsing before reporting the first twinge of pain. Non-deprived smokers had the shortest period to onset of pain. The longer the smokers had been deprived of cigarettes, the longer before the onset of pain. Non-deprived smokers also had a significantly shorter period of pain tolerance compared to deprived smokers. Non-deprived smokers tended to have a faster pain onset and a shorter tolerance period compared to non-smokers. Smokers' indices of pain were significantly higher on the several sub-scales describing the qualitative pain experience compared to non-smokers and to smokers deprived of cigarettes for more than one hour. Deprivation of cigarettes appears to diminish smokers' sensitivity to pain significantly below that of non-smokers and smoking cigarettes tends to heighten sensitivity to, or beyond, the level of non-smokers.

Smoking behavior of scientists

Academic biologists, chemists, mathematicians, and psychologists were surveyed to examine smoking rates among the various groups of scientists and to compare publication differences associated with smoking status. Smoking rates among these groups of scientists were, in general, quite low. A consistent tendency for greater publishing activity on the part of smokers than non-smokers or former smokers was observed.

Tobacco smoking and cortical evoked potentials: an opposite effect on auditory and visual systems

1. Auditory and visual evoked potentials produced by five intensities of tones and light flashes were recorded in twelve young men who were habitual smokers. 2. The subjects attended the laboratory on four occasions. Two recordings were made on each of the last three of these visits. They were made (i) before and after smoking, (ii) without smoking, (iii) before and after smoking after 12 h abstinence from smoking. 3. Smoking was associated with increases in the amplitudes of the components V-VI, VI-VII in the visual system and a decrease in the amplitude of N2P2 in the auditory system. Abstinence from smoking produced effects in the opposite direction. 4. These findings are consistent with the possibility that smoking has different and perhaps opposite effects on the visual and auditory system. 5. The findings may be helpful in re-evaluating some of the apparently conflicting reports on the effects of smoking on perceptual processes.