WASHINGTON (AP) — It's pretty extraordinary for people in their 80s and 90s to keep the same sharp memory as someone several decades younger, and now scientists are peeking into the brains of these "superagers" to uncover their secret.

The work is the flip side of the disappointing hunt for new drugs to fight or prevent Alzheimer's disease.

Instead, "why don't we figure out what it is we might need to do to maximize our memory?" said neuroscientist Emily Rogalski, who leads the SuperAging study at Northwestern University in Chicago.

Parts of the brain shrink with age, one of the reasons why mo...