It utilized to be thought that neurons cannot reproduce–that once confirmed neuron died, it would never replaced. It has turned to become false. Neurons sometimes reproduce. But occasionally they don’t. Issue: When do they reproduce? My guess is that, whenever a neuron dies that’s component of an normally undamaged brain-structure, after that that neuron will become changed; but when an entire brain-structure is destroyed or severely damaged, that structure will not be replaced and, as a result, the neurons that composed it also will not be changed.