Why do brain nerve cells undergo little cell division after embryonic development?

Brain nerve cells, or neurons, undergo little to no cell division after embryonic development because they reach a state of terminal differentiation.12

In the process of cell differentiation, cells progress from an undifferentiated state to a specialized, mature form. Once a neuron reaches this final, specialized stage, it is generally no longer capable of division. Unlike tissues such as skin, which rely on a population of stem cells to constantly replace lost or damaged cells, the central nervous system lacks a similar mechanism for the widespread replacement of entire neurons.12

Furthermore, the division of cells in the adult body is a highly regulated process, and in the case of neurons, they are often prevented from dividing by specific molecules produced by neighboring cells. Consequently, the maintenance and repair of the adult brain rely on the growth of existing neurons, the formation of new synaptic connections, and the support of glial cells rather than the generation of new nerve cells.23