Why is the mental exhaustion with excessive brain?

Time of meditation often makes people feel tired. Why is this? Recently, a new study by French researchers found that long -term attention concentration will cause glutamic acid to accumulate in the front area of ​​the brain, and excessive glutamic acid will make further brainpower work difficult. Related research results were published on August 11 in "Contemporary Biology".

The person in charge of the research and Antonius Wiehler, the Paris Institute of Paris, explained that excessive glutamic acid has potential harm to the human body. The brain wants to avoid this, so it will try to reduce activities.

Many people have experienced mental fatigue. After working hard, the brain does not seem to exhaust energy, and even when we do not deliberately think about any specific things, some brain areas are still as active as before.

In order to learn more, the Wiehler team used magnetic resonance spectrum (MRS) technology to measure the level of various chemicals in the living tissue. Researchers concentrate their attention in the front of the brain and a area on both sides, that is, the outer frontal premiral cortex. Many previous studies have shown that this area is related to complex intellectual tasks.

A total of 40 participants conducted MRS scanning memory tests. This includes the number sequence appearing on the screen, and it shows whether the current number is the same as the previous number. 26 participants completed more difficult tasks, while other 14 participants completed simpler tasks.

Researchers also measured the level of eight different brain chemicals, including glutamic acid (the main signal chemicals between neurons). Studies have shown that the electrical signal cannot cross the connection between the neurons (synapses), and can only rely on the release of tiny particles such as glutamic acid to pass the signal.

After completing a 6 -hour memory task, compared with the beginning of the experiment, the level of glutamate levels of the outer frontal prefabal cortex who experienced more difficult memory tasks has improved. The level of glutamic acid of those who do the simpler tasks remains unchanged. Among all participants, the seven other cerebral chemicals measured did not increase.

Among the participants who do the difficult tasks, the rise in glutamic acid levels is consistent with the expansion of the pupils, and the latter is another indicator of fatigue. At the same time, those who do simple tasks have not risen or the pupils are enlarged.

Researchers also investigated whether mental fatigue would affect decision -making. They can achieve this through different exercises in memory tasks, such as making people make choices between directly getting a sum of money and getting another money later.

As the participants feel more tired when doing more difficult tasks and accumulate glutamic acid, they will turn to the option to give a small reward immediately. This may be an example of people's mental tasks that avoid difficulties, such as calculating what options to do, thereby preventing the accumulation of potential harmful glutamic acid.

"One way to reduce glutamic acid accumulation is to reduce the prefrontal cortex when choosing." Wiehler said that if this is done, it means that you choose a seductive option.

RETO Huber of the University of Zurich, Switzerland, believes that measuring the degree of effort to reveal the work of a brain can be used. Therefore, doctors may use it to evaluate those who are difficult to concentrate, such as children who have suffering from defects and multiple disorders. (Xin Yu)

- END -