How do we know where we are? How do we get from point A to point B? What helps the brain navigate places we’ve been before? The Nobel Prize was awarded for answering these questions.
The Nobel Assembly at the Karolinska Institute of Medicine in Stockholm has announced the names of the 2014 Nobel Prize winners in Physiology or Medicine. The award ($1 million) is divided equally between the British scientist of American origin John O’Keefe and working together Norwegian spouses May-Britt Moser and Edward I. Moser. The prize was awarded for the discovery of neurons that provide orientation in space. In a press release from the Nobel Assembly, to the delight of journalists, neurons are called “the GPS system of the human brain.”
The first hero, O’Keeffe, was awarded the award 43 years after he discovered that, depending on where in the room the laboratory rat is located, certain cells in the hippocampus structure are activated in its brain (brain structure, located on both sides in the temporal region). Thus, the brain, associating certain cells with certain locations, draws a map of the area, as it were, and the memory of it is one or another combination of activated “location cells”.
This discovery is the answer of modern science to the German philosopher Immanuel Kant, who suggested that a person has a priori knowledge, that is, knowledge “embedded” in the mind and independent of experience, including about space and time. It turns out that the great thinker was right, at least in part: the ability to comprehend space is indeed built into the brain in the form of a “hard carrier” – nerve cells.
In 2005, thanks to the research of May-Britt and Edward Moser, who, by the way, consider themselves students and followers of O’Keeffe, it turned out that this mechanism is even more complicated. In the entorhinal cortex, located near the hippocampus, they found a repeating pattern of activation of certain neurons, depending on the movements of the rat.
These cells are called grid-neurons, i.e. grid neurons. Their function is to structure the spatial information coming from the “location cells” in the form of hexagonal grids that serve as a coordinate system, and each grid neuron reacts in its own unique way, and together they form a navigation “tool”.
In addition to “location cells” and grid neurons, the “brain GPS” system includes cells that recognize the position of the head and direction of gaze, as well as the boundaries of the room; they are also located in the entorhinal cortex.
Later, brain scanning technologies and neurosurgical operations on the brain made it possible to find location cells and grid neurons in humans as well. It is known that in patients suffering from Alzheimer’s disease, the defeat of the hippocampus and entorhinal cortex is noticeable already in the early stages of the disease. Therefore, now it is not surprising that one of the first in Alzheimer’s disease is precisely the ability to orientate in space, the ability to remember and find the way home.
The discovery of the brain’s navigation system represents a quantum leap in science – it is now clear how “ensembles” of specialized cells, working together, provide higher nervous functions. It opens up new perspectives in the study of other cognitive processes, such as memory, thinking and planning, says a press release from the Nobel Assembly.
For more information see The Official Site of the Nobel Prize, nobelprize.org
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