Brain waves can not only be used in the basic theoretical research of brain science, but also have a more important significance in that they are closely related to our life and health. 1. EEG is a method to record brain activity by using electrophysiological indicators. When the brain is active, a large number of neurons produce postsynaptic potentials synchronously, and these potentials are accumulated. It records the changes of electric waves during brain activity, and it is the overall reflection of electrophysiological activities of brain nerve cells on the surface of cerebral cortex or scalp. 2. Brain waves originate from the postsynaptic potentials of dendrites at the top of pyramidal cells. The formation of brain wave synchronous rhythm is also related to the activity of cortical thalamic nonspecific projection system. 3. EEG is the basic theoretical research of brain science, and EEG monitoring is widely used in clinic. 4. Bioelectricity is one of the basic characteristics of life activities. All kinds of living things have manifestations of electrical activity, from whales to bacteria, all have bioelectricity with different strengths. In fact, the word "cell" in English also means battery. Countless cells are equivalent to miniature small batteries and are the source of bioelectricity. There are many nerve cells in the human brain that are active, resulting in electrical changes. In other words, there is an electric pendulum. And this kind of swing appears on scientific instruments and looks like waves. The electric vibration in the brain is called brainwave. Explaining brain waves in one sentence may be said to be the biological energy produced by brain cells, or the rhythm of brain cell activity.