CELL BIOLOGY, NEUROPHYSIOLOGY
A type of neuron in the brains of many species which allows them to position themselves in space, thus acting as an internal GPS.* These cells are located in triangular grids of synchronised neurons**.
*Global positioning system **Their existence was predicted by WH Calvin in his 1996 monograph The Cerebral Code, based on the recurrent collateral branches in neocortical pyramidal neurons which had synaptic clusters at standard spacing. May-Britt and Edvard Moser (Norway) discovered grid cells in 2005, for which they shared the 2014 Nobel Prize in Physiology or Medicine. The accompanying image shows the trajectory of a rat that ran through a square environment in black. The red dots indicate places at which a particular entorhinal grid cell fired. It’s a bit rough, but one can appreciate the triangular spacing of the neuronal action potentials.