This month the Nobel Prize for physiology and medicine was awarded to a team of researchers who discovered the brain’s ‘GPS system’. This is a significant step forward in the world of science and relates to each and every one of us. Everytime you go home you remember where your room is; and when you’ve lived in a house for a while, have you ever experienced the ‘autopilot’ feeling that you get when know exactly where you’re going despite not being consciously focused on it? We know surprisingly little about how and why we know exactly where we are in space at all times, and this Nobel Prize is a ‘breakthrough’ of sorts into this area of neuroscience.
The first component of this discovery actually happened in 1971. A neuroscientist named John O’Keefe found that a certain type of nerve cell in the hippocampus was always activated when a rat was in a certain position, and other nerve cells were activated when the rat changed place. This experiment showed that cells simply known as ‘place cells’ within the hippocampus formed a ‘map’ of a room, and so influenced the rats’ experience of spatial positioning.
May-Britt Moser and Edvard Moser’s award-winning discovery built upon this experiment. They wanted to assess just how the ‘place cell’ activation signal was fired, and by inactivating different parts of the brain, and then assessing the direction of ‘information flow’, they discovered that the information required to activate place cells came from an area of the brain known as the entorhinal cortex, a largely unexplored structure. By studying this area, the Mosers found that some neurons fired when the rats moved into a particular place, and other neurons fired when the rats moved place. It seemed there was no visible pattern when the rats moved around small areas, but when the space was extended it was found that the neurons were firing in a pattern of near hexagonal lattices. That is to say, that every time the rat moved into a different hexagon, another neuron fired, until the whole space was conceptualised using hexagonal shapes within the brain. These shapes form a ‘grid’, which helps to create a neural ‘map’ of the area and the rats’ positioning within it. These neurons were then called grid cells, and since this discovery the Mosers have also noted that this effect remains the same in the dark, and is independent of movement speed or direction. Moreover, they discovered that these hexagons together form a cluster of cells that, assuming humans have the same spatial configuration as rats, unconsciously keep track of our navigation wherever we go.
Though this is merely a discovery of the mechanism of the brain’s GPS system, and not an explanation as to how or why it works in such a way, this presents a number of new opportunities for the scientific world that were never imaginable before. The most salient application would perhaps be in mental health conditions such as dementia, and a fuller understanding of the brain’s positioning system may allow physicians and pharmacologists to develop new treatments to combat the severe and dehabilitating effects that such a disease has on an individual’s sense of place. It could even tell us more about how the disease as a whole develops and operates. In addition, a discovery like this could have significant consequences for technology and robotics. Cognitive science seeks to understand the brain in terms of its ability to process information- and likens the mind to a computer system, working on an input, output and feedback system. So theoretically, if we can work out the neural ‘coding’ of the brain exactly, we can then apply this to a mechanical computerised system, and create computer systems with the equivalent of a conscious positioning system.
Of course all of these applications assume that rat ‘grid cell’ systems are similar to human positioning systems, and this may not be the case. Humans are far more complex than rats, and some psychologists would argue that the differences between them are so significant that it is rare that any result is directly applicable to humans. Though this may be true, this discovery provides us with previously unknown knowledge about how animals function in the world, and provides a foundation for some incredibly interesting and groundbreaking developments in the future.
Photo credit NTNU