Illustration of the Norwegian neuroscientist Edvard Moser (born 1962). Moser is best known for the discovery, with his then-wife and colleague May-Britt Moser, of grid cells in the brain. Their studies in rats showed that cells in the medial entorhinal cortex (MEC) fired multiple times and at different locations as the animals explored their environment. The firing occurred as a rat passed certain points arranged in a hexagonal grid in space, and so these cells form a coordinate, or positioning, system forming spatial representation of the environment. The Mosers and John OKeefe shared the 2014 Nobel Prize in Physiology or Medicine for their discoveries of cells that constitute a positioning system in the brain.