Internal TomTom

Source: Noorderlicht, photo Torkel Hafting
Rats as well as people have special brain cells for navigation. Not so much for driving to some holiday destination, but for walking in familiar spaces. Without thinking you walk to the dining table to the kitchen and to the couch.
The distance between the couch and the coffee table is known and therefore you do not walk into the table all the time. Research in rats has shown that two types of brain cells are involved in this in rodents. The ‘place cells’ store information about where the objects in a familiar space are located. The distances within the space are observed by ‘grid cells’. The grid cells form a highly regular diamond pattern. This grid is a virtual map of the environment. Every point on the grid matches an abstract coordination point in the environment. When the rat passes this point the brain cell in the grid sends out a signal. The distances between the brain cells in the grid correlate with actual distances. The scientists believe that these cells help the animals to navigate. Because the brain cells match abstract places in the environment the system also works in the dark.

A researcher from London University has now discovered that humans also possess such grid cells. Subjects had to navigate through a virtual space while their brain activity was measured in an MRI scanner. Brain cells were found to be active in a specific pattern. Also these cells formed a diamond grid.

So we are able to walk from our beds to the toilet, without bumping into everything. In theory, that is.