Wake up and smell the coffee

Many people like a cup of coffee to pick them up in the morning, but can caffeine actually boost your brain power? The few studies done so far have been fairly inconclusive, so Tino Zaehle and his colleagues at Otto-von-Guericke University in Magdeburg, Germany, decided to try investigating the issue with NIR spectroscopy.

As described in a paper in BMC Research Notes, they did this by attaching 32 NIR sensors to the heads of 10 volunteers and then getting them to perform a simple memory task. This involved pressing a certain button if a letter displayed on a computer screen was the same as the preceding letter and pressing another button if it was different. Each volunteer performed this task twice, taking 200mg of caffeine before the second round.

By conducting NIR spectroscopy with the 32 sensors, Zaehle and his team were able to determine the concentration of oxygenated and deoxygenated haemoglobin over much of the brain, reflecting changes in brain activity as the volunteers performed the tasks. In addition, before the volunteers performed each round of these memory tasks, they conducted a round of simply pressing the same button every time a letter was displayed. This acted as a control, allowing the researchers to distinguish changes in blood activity caused by the volunteers using their working memory from those caused by simply reacting to the letter and pressing the buttons.

The researchers found that the concentration of oxygenated haemoglobin in an area of the brain called the bilateral inferior frontal cortex, known to be involved in working memory, was lower when the volunteers performed the task after taking caffeine. This makes sense, because caffeine is known to constrict capillaries in the brain, which would have the effect of reducing the flow of oxygenated blood to active areas.

However, this didn’t seem to have any effect, positive or negative, on the volunteers’ cognitive abilities, because their performance on the memory task was just as good whether or not they had taken caffeine. Where caffeine did boost their performance, however, was in the control trial, with the volunteers reacting faster after taking caffeine. This all suggests that while that cup of coffee may give you a basic early morning boost, it won’t actually help you think any clearer.

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