"[C]an an old brain learn, and then remember what it learns? Put another way, is this a brain that should be in school? As it happens, yes. While it’s tempting to focus on the flaws in older brains, that inducement overlooks how capable they’ve become. Over the past several years, scientists have looked deeper into how brains age and confirmed that they continue to develop through and beyond middle age. Many longheld views, including the one that 40 percent of brain cells are lost, have been overturned. What is stuffed into your head may not have vanished but has simply been squirreled away in the folds of your neurons.