The grid cells used information about direction and speed in order to find the location.
In the experiment conducted by the Mosers', rats were made to run a constricted 4 meter long track.
In order to eliminate the response of nearby entorhinal cells on the readings, a second experiment was conducted.
The grid cell in turn uses this information along with the head direction in order to calculate the location of the animal in the cognitive map.
This area contains most of the cells involved in cognitive mapping and this could suggest why patients suffering from Alzheimer's disease tend to forget or become lost.