How can we know where we are? This question has for centuries pestered philosophs. In the area of GPS this now is no longer even a practical question, anyone with a smartphone can easily determine her/his position in space with unprecedented certitude.
However, what is technically possible, does not bear on the perception of space in the human mind. Agreed, that this would pose problem came not even to my mind. Therefore, the announcement of the Nobelprice to the three researchers John O’ Keefe (USA) and the couple May-Britt and Edvard Moser (Norway) comes as a surprise. But it shows that there was a question and already the solution these three researchers provided. I cite from the press release of Nobel Assembly at the Carolinka Institute (Nobelprizse.org):
The discoveries of John O´Keefe, May-Britt Moser and Edvard Moser have solved a problem that has occupied philosophers and scientists for centuries – how does the brain create a map of the space surrounding us and how can we navigate our way through a complex environment?
John O´Keefe and the place in space
John O´Keefe was fascinated by the problem of how the brain controls behaviour and decided, in the late 1960s, to attack this question with neurophysiological methods. When recording signals from individual nerve cells in a part of the brain called the hippocampus, in rats moving freely in a room, O’Keefe discovered that certain nerve cells were activated when the animal assumed a particular place in the environment (Figure 1). He could demonstrate that these “place cells” were not merely registering visual input, but were building up an inner map of the environment. O’Keefe concluded that the hippocampus generates numerous maps, represented by the collective activity of place cells that are activated in different environments. Therefore, the memory of an environment can be stored as a specific combination of place cell activities in the hippocampus.
May-Britt and Edvard Moser find the coordinates
May-Britt and Edvard Moser were mapping the connections to the hippocampus in rats moving in a room when they discovered an astonishing pattern of activity in a nearby part of the brain called the entorhinal cortex. Here, certain cells were activated when the rat passed multiple locations arranged in a hexagonal grid (Figure 2). Each of these cells was activated in a unique spatial pattern and collectively these “grid cells” constitute a coordinate system that allows for spatial navigation. Together with other cells of the entorhinal cortex that recognize the direction of the head and the border of the room, they form circuits with the place cells in the hippocampus. This circuitry constitutes a comprehensive positioning system, an inner GPS, in the brain
We like to congratulate as well.