The Neurons That Tell Time

In June of 2007, Albert Tsao, a nineteen-year-old native of Silver Spring, Maryland, was working in Trondheim, Norway, at the Kavli Institute for Systems Neuroscience. Tsao was a summer intern in the lab of May-Britt and Edvard Moser, married researchers who were well known in neurobiology circles for discovering "grid cells"--neurons that, by tracking our position, create a navigational map in the brain. Grid cells are located in an area of the brain called the medial entorhinal cortex. Tsao was curious about the relatively uncharted region next door--the lateral entorhinal cortex, or L.E.C. After implanting tiny electrodes in the L.E.C.s of some rats, he set them foraging for bits of chocolate cereal in a series of boxes, some black, some white.