Abstract: This talk will focus on the neural substrate of our ‘sense’ of space and the methods used to decipher this neural code. I will show how the entorhinal cortex and hippocampus of the mammalian brain form a dynamically updated map of external space. Research from my lab has demonstrated that cells in the entorhinal cortex are part of a universally applicable neural map for space, consisting of multiple functionally specialized cell types entangled in a complex neural network. A key cell type is the grid cell, which we discovered in entorhinal cortex in 2005. Grid cells fire selectively at regularly spaced positions in the environment such that, for each cell, activity is observed only when the animal is at places that collectively define a repeating triangular pattern tiling the entire environment covered by the animal, much like the holes of a Chinese checkerboard or a bee hive. The spatially periodic activity pattern provides the brain with a metric for distance as well as direction. I will show that, together with direction cells and border cells, grid cells generate a dynamically updated map of current location that may be used when we try to find our way from one place to the next.