Caffeine effects on perceptual and motor processes.

The effects of a single dose of caffeine on specific information processing operations were examined by using a visual selective attention task in which subjects were asked to select between a left and right hand response on the basis of two different target letters. The target was presented on a predefined position in the visual field and was either presented alone or with flanker letters, calling for the correct, the incorrect or no specific response. A dose of 3 mg/kg body weight caffeine or lactose, dissolved in a cup of decaffeinated coffee, was administered double blind and deceptively to overnight abstinence coffee drinkers. Behavioural measures were supplemented by psychophysiological measures. The present results replicated the basic findings obtained in this paradigm. The results indicated that the time to localise the target decreased and response preparation started earlier after caffeine than after placebo. These caffeine effects did not interact with the time subjects spent on the task or with the reaction time distribution, which might be due to a high level of practice.

RCT Entities:   Population Interventions Outcomes