If you overuse your brain, will it become "overloaded" like an electrical appliance?

At the end of December, it is the "exam season" for school students. Many students are worried while reviewing their lessons: Will they suffer from neurasthenia if they concentrate so much every day? Will their brains be "overloaded" like electrical appliances due to overload? I am often asked such questions when I give popular science lectures on brain science. It seems that everyone is still worried about damaging this delicate and magical organ due to improper use.

In fact, the brain is not as fragile as we think, it has the ability to protect itself. First, when the metabolic products of brain cells accumulate to a certain level, people will feel sleepy, and the human brain will naturally rest through sleep. Secondly, the brain contains a large number of inhibitory neurons, which select signal input and adjust signal output, which makes the brain always in a state of balance between excitement and inhibition. Thirdly, the working principle of the human brain is to generate and transmit electrical signals, unlike muscles, which consume a lot of ATP (adenosine triphosphate, an energy system that supplies energy in the body) to do work. Therefore, compared with muscles, the human brain is a typical "low-energy" organ. When a person performs high-intensity physical labor, his appetite will increase greatly, while when performing high-intensity mental labor, his appetite will be about the same as usual. This also reflects from the side that the brain will not consume excessive energy due to thinking about problems, and it is not easy to have the problem of "overload".

People often say that "the more you use your brain, the smarter it gets." Those famous scientists, philosophers, and writers do not increase the risk of diseases such as neurasthenia due to deep thinking. On the contrary, they are usually healthier and live longer than ordinary people. When the brain concentrates on thinking about a problem, the neural circuit changes from the free and undisciplined default operation mode to the focused task activation mode. The number of neurons activated in the two is similar, but the distribution area is different. For example, when the brain concentrates on thinking about a problem, it is like the light of a flashlight is focused, which looks bright, but the power consumption does not increase.

What kind of people will suffer from neurasthenia? They are often those who "think too much". "Thinking too much" is different from "thinking about problems". The former must be accompanied by obvious negative emotions, such as confusion, fear, worry, tension, anxiety, etc. At this time, not only is the cerebral cortex thinking hard about the problem, but the nuclei related to emotions in the limbic system are also highly excited, and various physiological reactions occur through nerve and body fluid regulation, such as panic, chest tightness, shortness of breath, restlessness, etc. If it continues to develop, it may become depression, anxiety, obsessive-compulsive disorder and other mental disorders.

Let's take the story of Wang Yangming "grinding" bamboo to see what "overthinking" means. Wang Yangming heard that "every blade of grass and every tree contains the ultimate truth", so he looked at the bamboo in the yard and wanted to "grind" out the heavenly truth in the bamboo. He and a classmate named Qian stared at the bamboo from morning to night, thinking hard about what heavenly truth there was. As a result, after staring for three days, classmate Qian fainted, and Wang Yangming continued to "grind" the bamboo alone. On the seventh day, his eyes went black and he lost consciousness. At that time, he misunderstood the meaning of Zhu Xi's original words and thought that he could immediately comprehend the eternal truth from one thing. The result was a failed attempt. After Wang Yangming realized the truth, whether he was discussing the subtle theory of mind with friends or students, or suppressing the rebellion of Prince Ning with wisdom and courage, the above scenes did not appear again, because he had a firm mind and was no longer troubled by emotions, so he could think and judge calmly.

Let's take exams as an example. If you study hard and maintain a good life routine, you won't have the problem of overusing your brain. If you study late into the night, you will feel dizzy and lose your concentration. If you worry about what to do if you don't do well in the exam, and then wonder if you can ask a classmate to help you, you will imagine the teacher's reproach, your parents' resentment, and your classmates' contempt... Not only will you not be able to remember the knowledge, but your physical and mental health will also be harmed.
How can we think seriously without overthinking? The Great Learning says: "Only when we know how to stop can we be determined, only when we are determined can we be calm, only when we are calm can we be at peace, only when we are at peace can we think, and only when we think can we achieve." "Stop" means to stop at the highest good, and "determination" means to have a determined mind. With such a foundation, the mind will be calm and will not be disturbed by external things. Then we can think carefully and discern clearly, and achieve something through action. This is the effort of Confucian practice, and it is also a magic weapon for obtaining health and happiness. How to know and act specifically, everyone needs to face their own situation and think about it.

(The author is an associate professor at Central China Normal University and a member of the Science Popularization and Continuing Education Committee of the Chinese Society of Neuroscience)