In what researchers are hailing as a major advance, a British man has undergone a stem cell injection to repair brain damage he sustained in a stroke.

It's been a big couple of weeks in Alzheimer's research. First, as we reported, the news broke that a little regular walking may go a long way in protecting your brain against Alzheimer's disease. Now, some Finnish researchers are contending that a diet rich in vitamin B12 can also serve as a bulwark against cognitive decline.

Belgian scientists announced in this week's Archives of Neurology a technique that may allow doctors to predict the onset of Alzheimer's disease much more accurately. But get the whole story before you celebrate.