Nobel Prize in Medicine for the decoders of the orientation system
How do we know where we are? For most people, the answer is simple - we open our eyes and observe. However, our ability to do this simple action, which we perform hundreds of times a day, is based on a very complex infrastructure system in the brain, which includes the vision system, memory, and a combination of input from other senses and motion sensors. The question of how this system works, and how animals (including humans) orient themselves in space and are able to navigate their way between different places, has occupied researchers for many years. The first to provide a clue to the solution was John O'Keefe. He was born in New York in 1939, and after graduating with a bachelor's degree at City College, he went on to earn a doctorate at McGill University in Canada, where he began to engage in attempts to study single brain cells. The brain is a tangled tissue of tens of billions of nerve cells and each cell can form an information network with hundreds or even thousands of other cells. When a brain cell works, it produces an electrical signal, or a certain sequence of signals, which are transmitted to the other cells, by electrical or chemical means. Among other things, O'Keeffe was involved in developing methods to measure the electrical activity of single cells. After his doctorate, he went to study at University College in London, where he was accepted in the late 60s as a full-fledged researcher in the pain research laboratory.
Rat location
O'Keefe studied in the brains of rats the activity of cells in the hippocampus (Hippocampus) - an area of the cerebral cortex that is known to be involved in memory, learning and spatial orientation among other things. He discovered in a group of cells that he examined a pattern of electrical activity that was not known before: certain cells that are active only when the rat is in a certain place in the room. When the rat was in the center of the room, certain cells in this group were active, and when it was moved to a corner, there was an increase in the electrical activity of other cells from the group. Each change of position produces a different pattern of activity, and thus a kind of neural orientation map is created in the brain. O'Keeffe and his partners called these cells "Place cells" and proved that they work separately from the normal sensory system. In further studies, O'Keeffe found that the brain produces such an orientation map in any environment in which the rust is found, based on the activity of the place cells. In studies done in the 80s and 90s, O'Keeffe and his colleagues showed that the location cells also serve as a component of the memory system, and allow the brain to keep orientation maps in different places. Researchers who followed him continued the studies on the location cells, better understood the mechanism of their activity, and found that they are involved in several other actions tangential to the field of spatial orientation, such as estimating distances.
together all the way
Edvard Moser was born in Oslo in 1962, and in 1985 he graduated from mathematics and statistics at the local university. That wasn't enough for him, so he also did a bachelor's degree in psychology and neurobiology. During his studies he met his wife May-Britt, who also studied psychology and hence their paths did not part. They did a doctorate in neuropsychology together at the University of Oslo, and when they finished in 1995, they went together to study in Edinburgh, and later in London, with John O'Keefe. There they entered the field of place cells, and tried to understand if there are cells outside the hippocampus that activate them. At that time it was known that a large part of the information in the hippocampus was received by cells in a nearby area of the brain, known as the entorhinal cortex. The weird ones thoroughly studied these cells, which they called "grid cells". They discovered that the cells are arranged in a hexagon around the area where the location cells are concentrated, and that a certain area in the hexagon begins to transmit electrical signals to the location cells, according to the direction of the rat's progress towards a certain area.
In the meantime, the strangers returned to Norway, and together they accepted professorships at the University of Trondheim. Together they founded the Brain Research Center and the Kavli Institute at the university, and mainly continued to research the brain's orientation system together. They discovered that the grid cells are part of a wider set of cells that are activated according to the direction of the rat's movement, or even the movement of the head. The discovery of this array and the interrelationships between the orientation cells discovered by the Strangers and the location cells discovered by O'Keefe, opened a first window to understanding how animals manage to orient themselves in space and the environment. By the way, May Britt and Edward Moser are the fourth couple in history to win the Nobel Prize in Science together. They were preceded in death by Marie and Pierre Curie (physics, 1903), their daughter Irene Julio Curie and her husband Frederic Julio (chemistry, 1935) and the couple Gertie and Karl Curie (medicine, 1947).
Well maintained system
Since the discoveries of the place cells and grid cells in rats and mice, researchers have proven that such cells still exist in many mammals. In humans, research on living subjects is of course extremely complex, but tests performed on epilepsy patients (the disease of falling), as part of a treatment in which electrodes are inserted into their brains, revealed that very similar cells also exist in humans. Further tests in the fMRI imaging device, brought up supporting evidence for the existence of such cells in our brain. The similarity between these systems in the examined mammals probably indicates the evolutionary importance of this orientation system. The learning ability of the system can be learned from a study done on taxi drivers in London, which showed that the drivers who were required to navigate large areas of the city without a map (even before the GPS era), had a very large hippocampus compared to other subjects. Since many diseases of the brain and nervous system impair the patients' spatial orientation, a good understanding of this system may be important both in understanding the mechanisms of such diseases, and in developing new treatment methods.
For previous articles on the subject on the science website:
Nobel Prize for Brain GPS Developers (Preliminary Report)
May-Britt and Edward Moser are the fourth married couple to win the Nobel together
