This should start with the principle of memory. The hippocampus in the brain plays a very important role in the formation and storage of memory. This product can restore people's memory. For example, for things that are often seen or mentioned, the hippocampus will extract them and store them for a period of time; If you repeatedly touch or recite (such as the strangest things like the most dazzling national style), then the hippocampus will transport them to the cerebral cortex to form long-term or permanent memories. Then, let's talk about the principle of dreams. I forget where the researchers studied it, saying that from light sleep to deep sleep, we have to go through a stage called rapid eye movement (REM), and dreaming happens at this stage. If you are awakened at this time and your dream is interrupted, then the memory will stay in your brain for a long time; But if the sleep quality is good, continue to sleep and enter the slow-wave sleep stage, that is, the deep sleep stage, the hippocampus begins to be passive, memory begins to lose, and dreams can't be remembered.