Image Edvard I. Moser Credit... Agence France-Presse — Getty Images

He told reporters that he was surprised to win a Nobel, Reuters reported, particularly after a “checkered” youth in which he studied the classics in school and aeronautics in college before venturing into philosophy and psychology.

Dr. Eric R. Kandel of Columbia University, who won a Nobel Prize for his research on the brain, said in an interview that before Dr. O’Keefe’s research, comparatively little was known about the hippocampus. “We knew it had something to do with memory,” he said, but not which hippocampal cells controlled which functions.

Dr. Kandel said he spoke with the Nobel Committee in support of Dr. O’Keefe’s nomination.

In 2005, the Mosers discovered a second crucial component of the brain’s positioning system by identifying other nerve cells that permit coordination and positioning, and calling them grid cells. While mapping connections to the hippocampus in rats moving about a room in a laboratory, “they discovered an astonishing pattern of activity in a nearby part of the brain called the entorhinal cortex,” the Nobel committee said.

When the rat passed multiple locations, the cells formed a hexagonal grid. Each cell activated in unique spatial patterns. Their research showed “how both ‘place’ and ‘grid’ cells make it possible to determine position and to navigate,” the committee said.

Image John O’Keefe Credit... Agence France-Presse — Getty Images

The Mosers were born to nonacademic families in rural Norway. Although they went to the same high school, they did not know each other well until they were undergraduates at the University of Oslo. They married while still in college and are now professors at the Norwegian University of Science and Technology in Trondheim. They have two daughters.