STOCKHOLM (AP) - How do we remember where we parked the car? And how do we figure out a shortcut to work when there's a big traffic jam?
The brain, it turns out, has a GPS-like function that enables people to produce mental maps and navigate the world - a discovery for which three scientists won the Nobel Prize in medicine Monday.
Husband-and-wife scientists Edvard Moser and May-Britt Moser of Norway and New York-born researcher John O'Keefe were honored for breakthroughs in experiments on rats that could help pave the way for a better understanding of human diseases such as Alzheimer's.
"We can actually begin to investigate what goes wrong" in Alzheimer's, said O'Keefe, a dual British-American citizen. He said the findings might also help scientists design tests that can pick up the very earliest signs of the mind-robbing disease, whose victims lose their spatial memory and get easily lost.
It was in London in 1971 where O'Keefe discovered the first component of the brain's positioning system.
He found that a certain type of nerve cell was always activated when a rat was at a certain place in a room. Other nerve cells were activated when the rat moved to another place. He demonstrated that these "place cells" were building up a map, not just registering visual input.
Decades later, in 2005, the Mosers identified another type of nerve cell - the "grid cell" - that generates a coordinate system for precise "positioning and path-finding," the Nobel Assembly said.
"I made the initial discovery over 40 years ago. It was met then with a lot of skepticism," the 74-year-old O'Keefe said. "And then slowly over years, the evidence accumulated. "And I think it's a sign of recognition not only for myself and the work I did, but for the way in which the field has bloomed."
John Kubie of the SUNY Downstate Medical Center in New York said this GPS system in the brain is used in such everyday tasks as remembering where a car is parked or taking a new shortcut on the way home.
Kubie also said learning about it may teach scientists more about how the brain learns and remembers, even apart from navigating.