I'm curious if the body breaks down dead neuron cells in the central nervous system. There needs to be space for neurogenesis. For instance, the spinal cord can only be so large, constrained by the spinal column. If there's not enough fluid between the nerves a stricture can occur.
Yes it does—a process called apoptosis that is a “clean” way for a cell to die.
A follow up question(s) that occurs to me are: “Do neurons die?”
What is the lifecycle of a neuron? Does it get replaced? Will a neuron, whose connections to the broader brain decayed or otherwise went away, continue to “live”?
I’ll go ask ChatGPT, but spare this rigorous community the unreliable answers to my passive interest.
So without sharing what ChatGPT said, I will say that assuming it is correct it makes a lot of sense on this topic alone why individuals engaged in lifelong learning live longer and are less prone to Alzheimers.