Nobel Prize for Medicine in 2014 for the "GPS of the brain"
The Nobel Prize in Medicine in 2014 belongs to John O'Keefe, on the one hand, and May-Britt Moser and Edvard other, for their work on brain cells that form a kind of "internal GPS".
Where am I, where am I going? How do I get from point A to point B and easily find my way? These questions have been a number of responses by the winners of the Nobel Prize in Medicine 2014: three physiologists discovered the cellular basis of a system of geolocation house located in the brain .
In 1971, John O'Keefe, a researcher from University College London, discovered the first cells involved in this kind of GPS internally. He recorded signals nerve cells in a part of the brain, the hippocampus in rats that were moving freely in a room. He then found that some cells were activated when the animal was in a certain place in the environment. These cells "positioning" (" Place cells ") were building a map of the environment. He concluded that the hippocampus generates many cards. Thus the memory of an environment would be stored in the form of a combination of activities cell positioning in the hippocampus.
More than 30 years later, in 2005, two Norwegian researchers, May-Britt and Edvard Moser have discovered other associated geolocation system cells of the brain : the "grid cells" ("grid cells") that allow positioning accurate. By constructing a map of the connections of the hippocampus in rats moved into a room, the two researchers found activity in a part of the brain near the hippocampus: the cortex entorhinal.
A GPS disrupted in Alzheimer's disease
The grids cells constitute a system that allows navigation in space. With other cells of the entorhinal cortex which recognize the direction of the head and the boundaries of the room, they form circuits with the positioning of cells in the hippocampus. Researchers have described how cell positioning and grids cells work together to allow the brain to know where it is and how to lead a movement.
Recent research using the brain imaging as well as observations on patients undergoing surgery of the brain, have provided evidence of the existence of these cells in humans.
Moreover, in patients suffering from Alzheimer disease, the hippocampus and entorhinal cortex are often affected at an early stage; Sometimes these patients tend to lose their way or not to recognize their environment. This work could lead to a better understanding of the mechanism of loss of spatial memory in patients by the Alzheimer's disease.