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Biomedical subjects

D M Warburton

Publications and source records attributed to D M Warburton.

At least 19 recordsLinked to original sources
PubMed1995

Effects of caffeine on cognition and mood without caffeine abstinence.

The objective of this study was to evaluate the effects of low doses (75 mg and 150 mg) of caffeine on mood and cognition in healthy people, with minimal abstinence of 1 h from caffeine. Improvements were obtained in cognition for attention, problem solving and delayed recall, but not immediate recall or working memory, but performance in the placebo condition was close to the maximum, giving little margin for improvement. For mood, there were statistically significant increase in clearheadedness, happiness and calmness and decreases in tenseness. These mood and performance-enhancing effects of caffeine cannot be seen as representing an alleviation of deficits induced by caffeine abstinence, because there was only minimal deprivation from caffeine.

Adolescent↗
PubMed1994

Improvements in performance without nicotine withdrawal.

Two tests were made of the withdrawal-relief explanation of the improvements in performance obtained with smoking. Study 1 examined the extent to which abstinence from smoking produced poorer performance in smokers in comparison with non-smokers. No evidence was obtained of differences in performance in smokers who were deprived of cigarettes for 10 h and non-smokers. Study 2 tested smokers with a standard cigarette or sham smoking after one hour and 12 h of deprivation. There was no difference in performance for the two deprivation intervals either in the sham smoking condition, or after smoking the lit cigarette. This study gave no evidence for withdrawal-relief being an explanation of the improvements in performance obtained with smoking.

Adolescent↗
PubMed1993

Exploring the limits of optimism: the case of smokers' decision making.

Smokers consider themselves less likely than others to contract smoking-associated diseases. This result has been interpreted as a weak form of irrationality. Alternatively, it can be interpreted as indicating that smokers show an optimism bias. The optimism explanation was examined by having smokers and non-smokers rate the likelihood of future negative events falling into three categories: (1) smoking associated, (2) health related and (3) health unrelated. Subjects rated their likelihood of the event happening to (1) themselves, (2) the average smoker and (3) the average non-smoker. Smokers and non-smokers rated their own likelihood of negative events as less than for the average smoker and the average non-smoker. But, while smokers rated their own risk as higher for both smoking-associated and other health-related problems, they rated their own risk as lower than the average smoker, a standard optimism bias.

Adolescent↗
PubMed1993

Cholinergic control of cognitive resources.

In this paper, we describe our approach to the investigation of cholinergic modulation of human information processing. In a continuing series of studies from our laboratories, we have systematically examined the extent to which current psychological models of information processing provide an adequate framework for the interpretation of the modulatory effects of cholinergic agents on cognitive performance measures. We suggest that the data are consistent with the view of attention and memory as processes which operate through a common, limited capacity executive mechanism, rather than separable serial processes described in the traditional modular models of memory.

Animals↗
PubMed1992

Nicotine issues.

This issue has covered most of the important concerns of nicotine researchers. Inevitably, there are gaps, because the selection of papers could only cover those which had been submitted or were known to be in preparation and about to be submitted. Nevertheless, these articles should serve to stimulate further discussion of and investigation into all aspects of nicotine use.

Humans↗
PubMed1992

A comparison of the attentional and consolidation hypotheses for the facilitation of memory by nicotine.

Studies examining facilitation of human memory by the administration of nicotine have given equivocal results and it has been argued that the positive findings on memory may have resulted indirectly from an effect on attention, rather than from a direct effect on memory storage. This study compared the "attentional" and the "mnemonic" hypotheses directly, by using both immediate and delayed recall tasks in a verbal free recall study, in which volunteers smoked on a fixed regime during presentation of a 32 word list (namely, one puff after each of eight 4-word blocks). The serial position curve for immediate recall demonstrated a significant improvement on the later blocks of the list (an attentional effect) when volunteers smoked a nicotine-containing cigarette. However, improved performance was found for items at the beginning of the list on the delayed recall measure and this improvement was significant on the first block of 4 words. Since nicotine input had been taken after presentation of this information, the results demonstrate post-learning facilitation of memory by nicotine.

Adult↗
PubMed1992

Facilitation of memory by post-trial administration of nicotine: evidence for an attentional explanation.

In human studies, reported performance improvements with post-trial administration of nicotine have all involved associative learning (Mangan and Golding 1983; Colrain et al. 1992; Warburton et al. 1992). In this study, post-trial nicotine, obtained through smoking a cigarette, improved free recall of lists of unrelated words under conditions which limited the opportunity for associative learning. However, the nicotine-induced advantage was not observed when volunteers were required to complete a secondary (attention) task during the post-trial period in which they smoked. The results suggest that post-trial effects depend on the opportunity for stimulus processing after input, and that nicotine improves performance by increasing the attentional resources available for such strategic processing.

Adolescent↗
PubMed1992

Effects of acute subcutaneous nicotine on attention, information processing and short-term memory in Alzheimer's disease.

This single-blind, placebo controlled study reports on the effects of administering three acute doses of nicotine (0.4, 0.6 and 0.8 mg) subcutaneously to a group of Alzheimer's disease (DAT) patients (n = 22), young adult controls (n = 24), and normal aged controls (n = 24). The study extends our previous findings obtained using smaller groups of subjects. Drug effects were examined on three computerised tests: the first measuring rapid visual information processing, sustained visual attention and reaction time (RVIP task); a delayed response matching to location-order task measuring sustained visual attention and visual short-term memory (DRMLO task); and a finger tapping test measuring simple reaction time (FT task). The critical flicker fusion test (CFF) was used as a measure of perception and the WAIS digit span forwards (DS), of auditory short-term memory. Tests were graded in difficulty, titrated to avoid floor and ceiling effects so that meaningful, direct comparisons between groups could be made. Nicotine significantly improved sustained visual attention (in both RVIP and DRMLO tasks), reaction time (in both FT and RVIP tasks), and perception (CFF task--both ascending and descending thresholds). Nicotine administration did not improve auditory and visual short-term memory. There were no consistent, overall patterns of difference in performance between smokers and non-smokers in the control groups, or between males and females in any group. Despite the absence of change in memory functioning, these results demonstrate that DAT patients have significant perceptual and visual attentional deficits which are improved by nicotine administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Nicotine as a cognitive enhancer.

1. Nicotine improves attention in a wide variety of tasks in healthy volunteers. 2. Nicotine improves immediate and longer term memory in healthy volunteers. 3. Nicotine improves attention in patients with probable Alzheimer's Disease. 4. While some of the memory effects of nicotine may be due to enhanced attention, others seem to be the result of improved consolidation as shown by post-trial dosing.

Animals↗
PubMed1991

A comparison of the effects of scopolamine and diazepam on working memory.

Two drug models of memory dysfunction, namely the benzodiazepine and the cholinergic models, have emerged from the considerable number of studies which have examined drug effects on information processing. The reported impairments produced by administration of compounds from these two families appear to be more similar than dissimilar, and to date, direct comparisons on traditional memory tasks have failed to differentiate the models. This study compared the effects of diazepam and scopolamine on tasks associated with separable components of working memory. The results indicate that this model also fails to discriminate between the drug models; both compounds selectively impaired tasks associated with the central executive mechanism and failed to disrupt tasks associated with the articulatory loop or the visuospatial scratchpad.

Adolescent↗
PubMed1991

Smokers of the future.

Teenagers continue to be initiated into smoking, especially young women. A predictor of smoking is the existence of stressors in their life. The major components of smoking motivation have been found to be similar in young smokers to those found in older smokers, except for the appearance of a group who are resisting the pressures against smoking. There is no evidence that the smokers of the future will be more extreme personality types than the smokers of 10 or more years ago. Changes in demographic characteristics of smokers in the United Kingdom and the United States in favour of relatively more women and more smokers from the poorer socio-economic groups requires investigation into whether this is attributable to different coping requirements in these groups.

Adolescent↗
PubMed1990

Puff-by-puff sensory evaluation of a low to middle tar medium nicotine cigarette designed to maintain nicotine delivery to the smoker.

Puff-by-puff assessments of a range of sensory and subjective attributes were made for three cigarettes, with tar and nicotine yields of: 10.0 and 1.4; 17.0 and 1.7; and 8.8 and 0.8 mg/cigarette, respectively. Seven attributes were assessed: mouth impact, throat impact, chest effect, roughness, intensity of flavour, satisfaction and quality of flavour. Significant differences between the three cigarettes were obtained for most of these attributes. Principal component analysis of the data revealed three principal components related to the cigarettes under investigation. Components 1 and 2 accounted for approximately 47 and 28% of the total variance and component 3 only added a further 7%. Principal component 1 was a complex combination of intensity-related characteristics, i.e. mouth and throat impact, chest effect, intensity of flavour, roughness, while quality of flavour and satisfaction contributed to the separation of samples on principal component 2. However, the two major components could not be defined simply in terms of the yields of tar and nicotine for the products determined on a smoking machine.

Adult↗
PubMed1989

Cognitive models and cholinergic drugs.

This paper reviews the use of cognitive models in human psychopharmacology to examine the role of the cholinergic system in memory and attention. We suggest that while studies of attention have continued to keep pace with developments in psychology, few studies have been reported which selectively test memory functions specified by current cognitive models of memory. We report the work from our laboratory which has demonstrated effects of cholinergic blockade on attention and memory, with particular emphasis on the work examining selective cholinergic mediation in working memory.

Attention↗