Small and other researchers at Columbia University Medical Center examined brains, young and old ones, donated from people who died without signs of neurologic disease. They discovered that a certain gene in a specific part of the hippocampus, the brain's memory center, quits working properly in older people. It produces less of a key protein called RbAp48.

That section of the brain, called the dentate gyrus, has long been suspected of being especially vulnerable to aging. Importantly, it is a different neural neighborhood than where Alzheimer's begins to form.

But the evidence that having less RbAp48 affects memory loss in older adults is circumstantial. So the researchers took a closer look at mice, which become forgetful as they age in much the same way that people do.

Sure enough, cutting levels of the protein made healthy young rodents lose their way in mazes and perform worse on other memory tasks just like old mice naturally do.

More intriguing, the memory loss was reversible: Boosting the protein made forgetful old mice as sharp as the youngsters again, the researchers reported in the journal Science Translational Medicine.

"Can we take an old mouse and now increase the levels of this protein in that very small area of the brain affected by aging and show that we can make an old mouse look like a young mouse," Small, who is also director of the Alzheimer's Disease Research Center at Columbia asked. "And we did."


Scientists find clue to reasons for age-related memory loss - CBS News