Neurobiology: Spatial orientation
Neurobiologists present a new theory for the origin of the grid cells required for spatial orientation in the mammalian brain, which assigns a vital role to the timing of trains of signals they receive from neurons called place cells.
20.07.2017
Excerpt from LMU press release of July 20, 2017:
New model for the origin of grid cells
Nerve cells in the brain known as place cells and grid cells, respectively, play a crucial role in spatial navigation in mammals. Individual place cells in the hippocampus respond to only a few spatial locations. The grid cells in the entorhinal complex, on the other hand, fire at multiple positions in the environment, such that specific sets are consecutively activated as an animal traverses its habitat. These activation patterns give rise to a virtual map, made up of a hexagonal arrangement of grid cells that reflect the relative distances between particular landmarks in the real world. The brain is therefore capable of constructing a virtual map which encodes its own position in space. The Nobel Prize for Medicine and Physiology 2015 went to the discoverers of this system, which has been referred to as the brain’s GPS. However, the developmental relationship between place cells and grid cells, as well as the mechanism of origin of grid cells and their disposition in hexagonal lattices remain unclear. Now LMU neurobiologists Professor Christian Leibold and his coworker Mauro Miguel Monsalve Mercado have proposed a new theoretical model, which for the first time provides a plausible model based on known biological processes. The model implies that the development of grid cells and their response fields depend on synaptic input from place cells. The new findings are described in the journal Physical Review Letters.