In humans, there are more than one hundred billion neurons. Each of them consists of processes and a body - as a rule, of several dendrites, short and branched, and one axon. Through the processes, neurons contact each other. In this case, circles and networks are formed along which the pulses circulate. Since ancient times, scientists have been worried about whether nerve cells are being restored.
Throughout life, the brain loses neurons. This death is genetically programmed. However, unlike other cells, they do not have the ability to divide. In such cases, another mechanism begins to act. The functions of the lost cells begin to be performed by the nearby ones, which, increasing in size, begin to form new connections. Thus, the inaction of dead neurons is compensated.
Previously, it was believed that nerve cells are not restored. However, this claim is refuted by modern medicine. Despite the lack of ability to divide, nerve cells regenerate and develop in the brain of even an adult. In addition, neurons can regenerate lost processes and communication with other cells.
The most significant accumulation of nerve cells is located in the brain. Due to the outgoing numerous processes, contacts are formed with neighboring neurons.
Cranial, autonomic, and spinal nodes, nerve endings, and nerves providing impulses to tissues, internal organs, and limbs form the peripheral part of the human nervous system.
The nervous system in a healthy body is a harmonious system. However, if in a complex chain one of the links ceases to fulfill its functions, the whole body may suffer. Severe brain damage accompanying Parkinson's disease, stroke, Alzheimer's disease lead to accelerated loss of neurons. For decades, scientists have been trying to answer the question of how nerve cells are restored.
Today it is known that the nucleation of neurons in the brain of adult mammals can be carried out using special stem cells (the so-called neuronal cells). At the moment, it has been established that nerve cells are restored in the subventricular region, the hippocampus (dentate gyrus) and the cerebellar cortex. In the last section, the most intense neurogenesis is noted. The cerebellum is involved in the acquisition and storage of information about automated and unconscious skills. For example, learning dance movements, a person gradually stops thinking about them, performing them automatically.
The most intriguing scientists consider the regeneration of neurons in the dentate gyrus. In this area, the birth of emotions, storage and processing of spatial information. Scientists have not yet been able to fully understand how newly formed neurons affect already formed memories, and how they interact with mature neurons in this part of the brain.
Scientists note that nerve cells are restored in those areas that are directly responsible for survival in the physical plane: orientation in space, smell, formation of motor memory. The formation of abstract thinking takes place actively at a young age, during brain growth. Moreover, neurogenesis is associated with all zones. Upon reaching adulthood, the development of mental functions is carried out due to the restructuring between the neurons of the contacts, but not due to the formation of new cells.
It should be noted that scientists continue to search for previously unknown foci of neurogenesis, even despite several rather unsuccessful attempts. This direction is relevant not only in basic science, but also in applied research.