We keep on growing neurons – even as we age THOMAS DEERINCK, NCMIR/SCIENCE PHOTO LIBRARY

Old age may have its downsides, but losing the ability to grow new brain cells isn’t one: healthy people in their seventies seem to produce just as many new neurons as teenagers.

The discovery overturns a decades-old theory about how our brains age and could provide clues as to how we can keep our minds sharper for longer.

In mammals, most brain cells are created at or soon after birth and are not renewed. Recently, it was discovered that the human hippocampus, associated with learning …