Why do people suddenly feel full while eating? Recently, a team from Columbia University in the United States found the answer in the brains of mice: a special type of neuron serves as a "satiety commander" responsible for issuing instructions to "stop eating". This study was published in the latest issue of the journal Cell. The reason why the newly discovered neurons are special is that they can integrate various information, such as the feeling of food entering the mouth, the feeling of stomach fullness, and even the nutritional components contained in food. In other words, they can not only "smell" or "see" food, but also "feel" the state of food in their stomach, and combine this information to decide when to stop eating. The team adopted advanced spatial resolution molecular analysis techniques. This technology can penetrate specific regions of the brain and distinguish different types of cells. When analyzing a complex signal processing area in the brainstem, the team discovered these previously unrecognized neurons. To verify the function of these neurons, the team modified them to be controlled by light. When these neurons are activated by light, the mice's food intake significantly decreases; The higher the intensity of activation, the faster the mice stop eating. Interestingly, these neurons not only send out simple "stop" signals, but also gradually slow down the feeding speed of mice. These neurons are inhibited by a hormone that increases appetite, which can be activated by glucagon like peptide-1 (GLP-1) receptor agonist, a drug commonly used to treat obesity and diabetes. Although these neurons were found in mice, the team stated that they are located in the brainstem, which is similar in the brains of all vertebrates. Therefore, humans are likely to have similar neurons as well.