ABSTRACT
RATIONALE AND OBJECTIVES: The Sternberg Memory Scanning task was used to test the hypotheses that immediate working memory (WM) would be impaired during moderate rising blood alcohol concentrations (BACs), and provision of a rewarding incentive for good performance under alcohol would counteract this impairment. METHODS: Two groups (n=18) of social drinkers received either 0.62 g/kg alcohol (A) or a placebo (P). Reward (verbal feedback and money) for good performance was provided to another pair of alcohol and placebo groups (n=18) (AR and PR). All participants completed two tests when BACs in the alcohol groups were rising (68 and 80 mg/100 ml) and two tests during declining BACs (73 and 64 mg/100 ml). RESULTS: Comparisons of A and P groups showed that rising BACs impaired immediate WM [increased errors, slowed rate of mental scanning, slowed reaction time (RT) when a larger number of items had to be held in WM]. Comparisons of AR and PR groups showed that reward for good performance during rising BACs counteracted impairment in scanning rate and RT but did not reduce errors. Tests during declining BACs of 73 mg/100 ml indicated some symptoms of impairment abated before others. When BAC declined to 64 mg/106 ml, the groups no longer differed on any measure of WM. CONCLUSIONS: An acute dose of alcohol can impair aspects of immediate WM performance while BACs are rising, and some of these effects can be reversed when incentives to perform well are provided.
Subject(s)
Ethanol/administration & dosage , Memory, Short-Term/drug effects , Task Performance and Analysis , Token Economy , Administration, Oral , Adult , Alcohol Drinking/blood , Alcohol Drinking/physiopathology , Analysis of Variance , Awareness/drug effects , Awareness/physiology , Drug Administration Schedule , Ethanol/blood , Female , Humans , Male , Memory, Short-Term/physiology , Reaction Time/drug effects , Reaction Time/physiology , Surveys and QuestionnairesABSTRACT
Past animal studies of the performance-enhancing properties of stimulant drugs, such as caffeine, may have suffered from a number of procedural and ethical problems. For example. the housing condition of the animals was often not taken into consideration. As well, endurance tests, such as the forced swim task, sometimes involved ethically (and procedurally) questionable interference with natural swimming behaviour. Some of the manipulations, such as attaching a weight to the swimming animal's tail to increase the difficulty of the task and using mortality as a dependent variable, seem grotesque, even unnecessary. In this experiment, the performance-enhancing effects of caffeine in a modified forced swim task and a dominance task were evaluated using male and female rats as subjects (N=60), housed in either enriched or isolated environments. Analysis indicated that rats respond to caffeine as an interactive function of sex, housing, dose, and task characteristics. It was concluded that performance-enhancing properties of stimulant drugs may be the result of a complex interplay of variables, making simple generalizations questionable.
