Somehow, when you get out of bed in the middle of the night, you manage to remember where the end of the bed is, how far it is to the bathroom and where the light switch is. You have developed a complex spatial memory of your house, and our brains are filled with countless other spatial maps (maybe some of us have fewer….cough, cough). How exactly does your brain encode this specific spatial information?
It turns out that is it using cells called grid cells, which work much like their name suggests. These neurons are spread out in a grid pattern in your brain and will generate an electrical spike in a pattern related to the direction you are moving. While this has been known about rats, mice and bats it has only recently been confirmed in humans. While fMRI experiments have suggested the existence of such cells, the only way to confirm that individual cells are spiking in response to a directional task is to make electrical recordings from them.