Interesting but not really a surprise because humans mature more slowly generally and live longer. No big news here that accounts for human uniqueness.
And it all happens without intelligence of any kind? “Expert guidance” without experts?
Notice that the neurons aren’t being called “junk neurons,” as in the exploded concept of vast libraries of “junk DNA.” Quite the contrary, they are given the somewhat glamorous cachet of “dark” neurons, as in “dark matter.” Perhaps something has been learned from the collapse of the concept of “junk DNA.”