Location! Location! Location!

Where are you? And how do you know? The answers find their most fundamental satisfaction through a mechanism in the temporal lobe discovered and explored by the three winners of this year's Nobel Prize for Physiology or Medicine. On Monday, the Nobel committee announced that John O'Keefe, May-Britt Moser, and Edvard Moser will share this year's prize for explaining the brain's global positioning system, a network of cells in the temporal lobe. In 1971, O'Keefe, now a professor of cognitive neuroscience at the University College London, first described what he called "place cells," neurons that identify specific places where a rat has been; the same neurons consistently activate whenever the rat walks by that location. Thirty four years later, the Mosers, who are a married couple and both professors at the Norwegian University of Science and Technology in Trondheim, discovered "grid cells." These neurons form clusters of triangular grids into which the place cells register their locations relative to each other.  Together, these two systems allow rats, humans, non-human primates, and probably most other brainy creatures, to determine their position in space, to store location information, and to navigate.

Last year, the first human grid cells were directly identified via electrodes temporarily implanted in the temporal lobes of epilepsy patients. The implants were put in place to study the patients' brains in preparation for surgery aimed at quelling their seizures. That work was done by Joshua Jacobs at Drexel University and appeared in  Nature Neuroscience.

The same area of the brain occupied by the grid cell navigation system is often hit by early Alzheimer's disease. Easily getting lost is a common early symptom of Alzheimer's.

James Gorman's good profile of the Mosers--who are both brilliant and adorable--was published in the Times last April.