If you feel drained at the end of a demanding day at the office, you may have been overthinking it.
Researchers have found that overuse of gray matter can lead to mental fatigue, making it difficult to make decisions.
The scientists analyzed the chemical composition of the brains of two groups of people over the course of an approximate working day.
One group was given easy tasks, while the other was told to carry out more demanding versions of the same cognitive tasks. Signs of fatigue, such as reduced pupil dilation, were recorded only in the group that performed the most complex tasks.
Using magnetic resonance spectroscopy, researchers at Pitie-Salpetriere University Hospital in Paris found that high-demand cognitive work led to a buildup of glutamate, a chemical that nerve cells use to transmit signals to other cells, in the area of the prefrontal cortex. Of the brain Managing the excess makes other prefrontal cortex activities, such as planning and decision-making, more difficult, leading subjects to favor low-effort, high-reward actions as cognitive fatigue sets in.
One of the study’s authors, Mathias Pessiglione, said previous theories suggested that fatigue was an illusion concocted by the brain to make us stop what we were doing and engage in a more rewarding activity.
But our findings show that cognitive work results in a true functional alteration, the accumulation of harmful substances, so fatigue would be a signal that makes us stop working, but with a different purpose: to preserve the integrity of the functioning of the brain. brain.
The researchers say that monitoring chemical changes in the prefrontal cortex could have practical implications, such as helping to detect severe mental fatigue to prevent burnout in the workplace.