As anyone who’s seen a yogurt commercial knows, our guts are teeming with bacteria. So, too, are our hands, feet, ears, and mouths.

But our brains?
Until recently, scientists would have said no way.
As anyone who’s seen a yogurt commercial knows, our guts are teeming with bacteria. So, too, are our hands, feet, ears, and mouths.
But our brains?
Until recently, scientists would have said no way.