Comment Maybe it's backwards science (Score 1) 12
They are looking at people who already have exceptional memories. The causation is that the super-agers stayed sharp because they exercised, were always learning new stuff, ate right and didn't let inflammation run wild. They lived their lives in build-mode instead of decay-mode. The baby neurons are the downstream of effect of not letting the system degrade.
They aren't super because their brains magically sprouted neurons, their brains sprouted neurons because their owners were super at living.