Having a basic sense of direction seems instinctive and simple for human beings, and it is. If we delve a little deeper into this subject, however, we may question how our brains make it possible to understand where we are. If we are lost, we can somehow figure out direction through memory and the aid of our inner GPS system. Yes, that’s right, our brains can reason and decide what direction we need to go, just like the navigational systems in our electronics.
How does it work?
Michael Chadwick and colleagues recently published a paper in the journal Current Biology and outlined which parts of the brain govern direction and how they work. It became apparent that two different tools were used for directional purposes: memory and internal maps.
The first major player in directional knowledge in the brain revolves around memory. Memory is short or long term images and information stored in the brain for later retrieval. Our memory can help up gain information about our surroundings and also help us orient ourselves according to our positions.
Of course, this gives rise to the belief that there must be a representation of this information that is stored, kind of like a map. This map would be imprinted upon the brain cells and be the main defense against getting lost. This map is vital for animals and for humans in order to have a correct sense of direction.
Locating Maps in the Brain
In 1970, the main directional map of the brain was located while testing the lab rat. The hippocampus appeared to be the source of this tool. As the rats moved about in an experimental environment, neurons fired within the hippocampus. The neurons firing, were tightly grouped into a space called “The place cells”.
What is learned?
Within the hippocampus and deep within the tightly grouped place cells, the map displayed images and information on both distance and direction. These factors were being stored in two different spaces of the “place cells”: with distance information found in the entorhinal cells (grid cells) and direction being stored in the head direction cells. Working together, the grid cells, which govern distance, fire in a tessellating pattern as the animal moves, providing a sense of distance that has been traveled. Information about direction, stored in the head direction cells, fires only when the animal is facing the direction of the destination. This well-oiled brain machine feeds information into the main place cells, which brings the system together.
This information was so outstanding that the 2014 Nobel Peace Prize in Physiology was awarded to John O’Keefe, the first to discover place cells and Edvard and May-Britt Moser, who identified grid cells.
Identify the direction of Home
Not only lab rats were studied, why of course not! Human subjects were tested to find out how they reason the direction of “home”. Using a virtual reality landscape, scientists discovered that most thinking and reasoning activity occurred in the entorhinal cortex. An MRI was also used to monitor changes in blood flow during this activity in the brain.
During neuronal firing, it was discovered that patterns were more similar than expected. When the person is facing the imagined goal direction, neurons act the same as if they are facing the correct direction of the goal. It seems that neurons can reason out the direction without even moving to face the “destination”. It seems that the neurons can actually help plan the route home!
With this information about navigational systems of the brain, we can understand how memory loss is such a traumatic occurrence. We can also understand why these areas of the brain that govern direction are the first affected by diseases such as Alzheimer’s.
Science has once again revealed an amazing aspect of our human condition. Not only does the body fight off diseases and repair itself — it is also a map! So, when lost, it’s not just animal instinct or trial and error that gets us home again. We are, in some ways, machines — well-organized with files and navigational systems, ready to offer us the direction to our destination. Again, we may find our direction in this existence by the genius of science!