The many maps of the brain

December 11, 2012

Spatial location is closely connected to the formation of new memories. Until now, grid cells were thought to be part of a single unified map system. New findings from the Norwegian University of Science and Technology demonstrate that the grid system is in fact composed of a number of independent grid maps, each with unique properties. Each map displays a particular resolution (mesh size), and responds independently to changes in the environment. A system of several distinct grid maps (illustrated on left) can support a large number of unique combinatorial codes used to associate new memories formed with specific spatial information (illustrated on right). (Credit: Tor Stensola, CBM/Kavli Institute for Systems Neuroscience)

Your brain has at least four different senses of location — and perhaps as many as 10 — and each is different, according to new research from the Kavli Institute for Systems Neuroscience at the Norwegian University of Science and Technology.

The brain has a number of “modules” dedicated to self-location, they found. Each module contains its own internal GPS-like mapping system that keeps track of movement, and has other characteristics that also distinguish one motion from another.

“We have at least four senses of location,” says Edvard Moser, director of the Kavli Institute.  “Each has its own scale for representing the external environment, ranging from very fine to very coarse.

“The different modules react differently to changes in the environment. Some may scale the brain’s inner map to the surroundings, others do not. And they operate independently of each other in several ways.”

This is also the first time that researchers have been able to show that a part of the brain that does not directly respond to sensory input, called the association cortex, is organized into modules. The research was conducted using rats.