Three scientists who helped discover how the brain knows where it is have won this year's Nobel prize for medicine.


American-British scientist John O'Keefe (left) won half the prize for his 1971 discovery of "place cells" in the brain, while Norwegian scientists May‐Britt and Edvard Moser (who are also a married couple) won for their 2005 discovery of "grid cells" in rats.
Together, the place cells and grid cells form the brain's "internal GPS", helping it work out where it is – and where it's going.
