The basic structure of the nervous system is neurons and the connections formed by nerve fibers. Identifying different types of neurons in different parts of the nervous system, revealing the efferent and afferent nerve fibers they constitute, and elucidating the neuroactive substances and receptors involved, provide the basis for the regulation of neuronal activity and the uncovering of how the nervous system works. It is also the goal of neuroanatomy research. The rapid development of modern science and technology and interdisciplinary penetration require us to conduct in-depth neuroanatomy studies on specific neural pathways composed of specific types of neurons using specific neuroactive substances for specific neural functions. This also provides a good opportunity for us to clarify the structure of nervous system and analyze its working principle from macroscopic, mesoscopic and microscopic levels.