Speedzellen Nobel Prize winners have tracked down speedometer cells in the brain

Tacho cells in the brain respond to speed
The two Nobel Prize winners May-Britt and Edvard Moser have discovered cells in the brain of rats that react to speed. These "speed cells" transmit signals at a higher frequency the faster the rodents move. This "brain tachometer" plays an important role in self-tracking, as the researchers write in the journal "Nature".

Speed ​​cells react to movement
The pair of researchers from the Norwegian University of Science and Technology in Trondheim received in 2014 the Nobel Prize for the discovery of halftone cells, which play an important role in space orientation. The discovery of speed cells is another major scientific contribution to the exploration of mammalian orientation.

Image: DigitalGenetics-Fotolia

"This is a big step forward," said Edvard Moser to the Norwegian newspaper "Adressavisen". "That was the missing puzzle piece in our research on location."

The researchers ran rats on a treadmill. For this they used a car in which instead of a floor, a corresponding device was installed. In this way, the researchers were able to precisely control the speed with which the rats ran on the tape. They chose seven, 14, 21 and 28 centimeters per second. Then the activity of the nerve cells was measured by electrodes in the entorhinal cortex and in the hippocampus. It turned out that certain cells became more active at an increasing rate than others. The entorhinal cortex is located immediately adjacent to the hippocampus and transmits signals to it. Both brain structures play an important role in spatial orientation and learning ability. As the researchers report in the journal, 15 percent of the nerve cells in the entorhinal cortex are speed cells, in the hippocampus their proportion is slightly lower at ten percent.

Activation of speed cells in the brain is independent of the environment
Further investigations showed that the activation of the speed cells is not related to the environment or the visual perception. Thus, the speed cells sent their signals in the same way regardless of a bright or dark experimental environment.

Together with colleagues, the researchers and researchers put forward the thesis that the spee cells at least partially receive their information from the regions in the brain that are responsible for the processing of self-perception and body movement.

Edvard Moser describes the speed cells opposite the newspaper "as a kind of speedometer. The activity increases in the cells as the rate at which the rat moves increases. This realization is an integral part of the 'internal map' that we have been working on for the last ten years. The map is dynamic and can not be updated without speed information, "explains the researcher. "It shows how the cells work together in the locating system of the brain."

Insights into speed cells are important for Alzheimer's research
In addition to the grid cells, which form a kind of internal map, so far still some other cells of the orientation system in the brain of mammals were known, such as the boundary cells for the identification of obstacles and the head-direction cells that work like a compass, as well as place cells.

May-Britt and Edvard Moser were awarded the Nobel Prize for Medicine in 2014 together with the British John O'Keefe. The Mosers discovered the grid cells in the entorhinal cortex in 2005, after O'Keefe in 1971 found the place cells in the hippocampus.

The results of the scientists are particularly important for Alzheimer's research, because the brain areas that serve orientation are among the first to be affected by the disease. As a result, Alzheimer's disease is common even before other symptoms of the disease appear. (Ag)