Under what circumstances will a human neuron divide?

Question

I read somewhere that a mature neuron loses its ability to divide, except for very specific situations. I was unable to find the description of those situations. What are they?

(I'm sorry I'm not saying where I read that, but I simply can't find it.)

Answer 1

Mature, differentiated neurons do not divide (undergo mitosis), but apparently there is a small population of self-renewing neural stem cells in adults that can produce new neurons. Neurogenesis predominantly occurs in the subventricular and subgranular zones of the brain.

Peripheral nerves can regenerate along its axon as long as the endoneurial tube and the Schwann cells are intact. Here's a picture of a neuron regenerating.

Answer 2

As was pointed out by @jello differentiated neurons do not divide, instead new neurons are recruited into existing networks from undifferentiated cells. This process is called neurogenesis. A high level summary of adult neurogenesis:

1. Neural progenitor cells differentiate into new neurons that have zero (or very few) synaptic connections, but are sensitive to the local chemistry.
2. (Optional) Sometimes (such as in adult neurogenesis in the olfactory bulb) these immature neurons-to-be are produced far away from where they are needed and follow standard pathways to migrate to the correct brain region
3. The immature neuron extends dendrites towards upstream neurons and starts to develop an axon
4. The immature neuron extends axon towards downstream neurons, and
5. The neuron matures and becomes indistinguishable from the network it joined.

For more information, consider the question: How are newly created neurons recruited into existing networks?