Zapping part of the brain makes you think harder – at a cost
Stimulating a part of the brain linked to mental effort boosts performance in demanding tasks, but also leads to greater mental fatigue afterwards
Brain zapping, or transcranial direct current stimulation (tDCS), may temporarily enhance mental performance, but it also increases mental fatigue, according to a study by researchers at the University of Munich. The study involved 31 volunteers who underwent a half-hour session in an MRI scanner while performing a demanding memory task called the 3-back test.
Some volunteers received tDCS stimulation to the dorsolateral prefrontal cortex (dlPFC), a brain region involved in controlling cognitive effort, while others received sham stimulation. Those who received tDCS performed better on the task, reacting faster and more accurately. However, they also showed higher levels of the neurotransmitter glutamate in their dlPFC, which could lead to mental fatigue.
The researchers suggest that taking breaks when feeling mentally tired could be beneficial. While the study provides strong evidence that tDCS can boost cognitive performance, it does not definitively prove that increased glutamate levels are the cause of mental fatigue. Other experts emphasize that the findings should not be extrapolated to real-world productivity, as the study only involved a short laboratory task.
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