STOCKHOLM - American-British scientist John O'Keefe and Norwegians May-Britt Moser and Edvard Moser won the 2014 Nobel prize for medicine or physiology for discoveries of cells that constitute a positioning system in the brain, the award-giving body said on Monday."The discoveries ... have solved a problem that has occupied philosophers and scientists for centuries," the Nobel Assembly at Sweden's Karolinska Institute said in a statement when awarding the prize of 8 million Swedish crowns ($1.1 million)."How does the brain create a map of the space surrounding us and how can we navigate our way through a complex environment?" the body added.Medicine is the first of the Nobel prizes awarded each year. Prizes for achievements in science, literature and peace were first awarded in 1901 in accordance with the will of dynamite inventor and businessman Alfred Nobel.