Until the second half of the twentieth century there was a view that central nervous system, after its evolution, was unable to any further regeneration. Moreover, it was said that neurogenesis (the development of nerve tissues) of an adult (postnatal) did not exist. However, in the course of time, some findings indicated that the process of new neurons was continuously formed in mature brains of primates as well as human beings. A breakthrough discovery of active, proliferating neural stem cells existing in a fully developed brain has given grave possibilitiesto modern neuroscience. The process of neurogenesis among adults is an extraordinary phenomenon. It plays an important role in a few processes. There is also evidence that neurogenesis may help answer the hippocampus to stress and prevent any onset of depression. Nowadays, it is identified to be three areas in the adult mammalian brain where processes of cell proliferation take place. These areas are: subventricular zone (SVZ), subgranular zone (SGZ) and posterior periventricular area (PPv). By excessive formating new tissues circulatory system is the opposite to the nervous system. Although the latter is the complex biological system with its cytostructure, neural network, the location of the functional centers and its integration it has a poor ability to regeneration. Because of the complexity of the central nervous system a few disorders can be distinguished such as: multiple sclerosis, ischemic stroke, Alzheimer’s disease, Parkinson’s disease or brain tumors. At present stem cells are matters of interest to scientists. Not only are stem cells being observed by researchers but also they are to be conducted studies on. The end result of these findings could be primarily usable for CNS regenerative therapies.