How does a brain know where it is? In 1971 John O’Keefe found neurons in the rat hippocampus that each fire only when the animal is in one particular place — “place cells”, a you-are-here signal. Decades later, in 2005, May-Britt and Edvard Moser found something stranger one step upstream, in the entorhinal cortex: “grid cells” that fire not at one spot but at many, laid out in a perfect hexagonal lattice that tiles the whole environment — a built-in coordinate grid. The three shared the 2014 Nobel Prize in Physiology or Medicine for discovering the brain’s map of space.
This exhibit lets you watch that map build itself. A virtual mouse forages a walled arena — drive it with the keyboard or let it wander — and as it covers ground, each spatial neuron paints its firing onto the floor in real time. The firing is the real model: a place cell is a Gaussian field, so it lights one blob; a grid cell is the rectified sum of three cosine waves sixty degrees apart, which mathematically forces a triangular lattice, so its blob repeats into hexagons across the entire floor. Pick different grid cells and you see different scales, orientations and phases — the bigger ones near the top of the hierarchy, the finer ones below.
The point is that space, to a brain, is not a picture but a computation — a set of firing patterns that together pin down location to a few centimetres, the same way latitude and longitude pin down a point on Earth. It is the cognitive map that lets you find your way home in the dark, and it degrades early in Alzheimer’s. The same idea — representing the world as patterns of activity over a population of cells — is the thread that runs through every exhibit in this wing, from a wasp’s 7,400 neurons to your own inner GPS.
Specifications
- Place cells
- Hippocampus — fire at a single location (O’Keefe, 1971)
- Grid cells
- Entorhinal cortex — hexagonal lattice tiling space (Moser, 2005)
- Model
- Gaussian place fields; grid = rectified sum of 3 gratings 60° apart
- Interactive
- Forage the arena, watch each cell’s real firing map emerge
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