Comment by someonebaggy

IIRC the slow loss of neurons is more than balanced by the additional fine-tuning - unless you get dementia, if course.

Loss of neurons isn't disastrous as long as it's not too many. Babies are born with several times more neurons than children have, and spend a few months letting all the useless ones die. Apparently it's better to start with a random tangle and prune it to shape (like cutting a box hedge) than to make a hedge grow in a box shape to begin with.

And IIRC brains can grow more neurons under some circumstances (certain drugs?) - they just normally don't.