After a busy day, almost everyone should have a good sleep. Of course, there are people who don't sleep all their lives, but that is very few. Sleeping is a physiological reaction, a part of brain nerve activity, and the result of inhibition of nerve cells in cerebral cortex after continuous excitement. When inhibition is dominant in the cerebral cortex, people will sleep. In life, people have work and rest, and in neural activities, people have excitement and inhibition. Inhibition is to protect nerve cells, make them excited again and let people continue to work. Yawning is the first signal to remind us of lack of sleep. If 18 hours don't fall asleep, people's reaction time will change from 0.25 seconds to 0.5 seconds, and continue to grow. Ordinary people will start to have paroxysmal drowsiness, anywhere, lasting about 2 to 20 seconds, and then you will find it necessary to reread what you have just read. Your eyelids are getting heavier and heavier. In 20 hours, you will start taking a nap. According to research, the reaction speed of normal people is basically the same as that of people with a blood alcohol content of 0.08-if you keep driving at this value, you will be detained in many countries. You will also forget many things, such as double-checking the spelling of your name, or setting the brakes when parking on a hillside. In the animal kingdom, sleep is as important as food, water and sex. Everyone from fruit flies to modern people is like this. But scientists can't know exactly what sleep does. Is it to refresh yourself? Not exactly. As we all know, muscles don't need sleep, they just need intermittent relaxation. Is it to keep a clear head? Close. A good sleep is good for the brain. However, scholars have not reached a consensus on how the brain benefits from sleep. One theory is that sleep helps the brain to store all the information that humans receive when they are awake. Another view is that sleep is to restore energy. It has also been suggested that sleep often uses some mysterious forms to help us master various skills. What is sleep? Two things happened in the mid-1990s, which brought the focus of research back to the real purpose of sleep. 1994, scientists from Weizmann Academy of Sciences in Israel suggested that scholars' research should focus on the problem of false memory processing, and the technology of peeping into the sleeping brain was greatly improved at that time. Scientists at Weizmann Academy of Sciences have found that the duration of people's rapid eye movement sleep is directly related to their ability to recognize fixed patterns on computer screens. This technique is called program memory, which requires repeated operation and practice. Memorizing facts, such as the name of the president of the United States, is declarative memory-an ability that has nothing to do with REM sleep. Robert, a neuroscientist at Harvard Medical School, said. Stickgold said: "Our understanding of memory is always naive." The function of sleep can be summarized as: (1) Eliminating fatigue and restoring physical strength: Sleep is the main way to eliminate physical fatigue. Because of sleep