According to a study, a glucose and caffeine combination can improve brain activity efficiency. Neural substrate for the combined effects of these 2 substances were identified making use of functional magnetic resonance imaging. The main study results were that the 2 substances combined improve cognitive performance in terms of working memory and sustained attention by increasing brain activity efficiency in the brain regions responsible for these 2 functions. This supports the notion of a synergistic effect between 2 substances, in which the effect of each one is boosted by the other.
The researchers found that all those who consumed a combination of glucose and caffeine showed reduced activation in areas of the brain brain connected to the task in the left prefrontal cortex and the bilateral parietal cortex – 2 areas that actively take part in working memory and attention processes. Brain activity reduction and the fact that no drop in behavioral performance was seen during the task indicates that the brain is more efficient under the 2 substances’ combined effect, as fewer resources are needed for producing the same performance level compared to those individuals who had the placebo or who had only glucose or caffeine.
The researchers made use of functional MRI for analyzing brain activity during the n-back task, to evaluate basic capacities for improvement of everyday cognitive tasks, such as working memory and sustained attention. 40 healthy participants were tested after drinking a beverage with either glucose, caffeine, or a combination of the 2, or a placebo with only water.
Prior research by the same researchers on the effects of glucose and caffeine consumption showed improvements in declarative memory and attention span with no significant alteration of the subjective state of the individuals. The conclusions indicated that a glucose and caffeine combination has beneficial effects on attention and learning and on verbal memory consolidation, none of which were seen when consuming the substances separately.