Question

why dont neurons undergoes mitosis

Answer 1

Neurons do not divide due to the reasons mentioned in Cornelius's answer. However, some new neurons can be generated in adults. Generation of new neurons in adults was first demonstrated in birds, where labeled DNA precursors could be found in differentiated neurons. Experiments in mammals and humans demonstrated later that new neurons are created in the central nervous system (CNS) in adults, although it seems to be restricted to some particular regions: granule cell layer of the olfactory bulb and dentate gyrus of the hippocampus. These new neurons seem to be local circuit neurons and interneurons (i.e. no long distance neurons). How are the new neurons produced if neurons cannot divide? They come from neural stem cells (NSCs) that were preserved in the sub-ventricular zone during development. NSCs are presumed to play a part in brain plasticity in the adult brain. However, they have therapeutic potential.