One of the most fundamental questions in neuroscience: how do people think? Until recently, we were far from a definitive answer, but in their study, scientists offer a new look at this problem and pay attention to the navigation system of our brain.
When traveling through space, two important cell types are active in the brain. By placing some cells in the hippocampus (part of the limbic system of the brain that is involved in the mechanisms of memory consolidation), and others in the neighboring entorhinal cortex, the brain forms a circuit that allows a person to navigate. A group of scientists led by Christian Doeller suggests that the same system may be key to thinking, and our knowledge, as they see it, is organized in a spatial way. The results of their research are published in the journal Science.
“If I think about cars, I can base myself, for example, on their horsepower and engine weight. So we get the idea of racing cars with a strong engine and light weight, and also about caravans with a weak engine and high weight - and even all combinations together. In the same way, we can think about our family and friends: for example, based on their height, sense of humor or income, perceiving them as high or low, funny or unfunny, more or less wealthy,”says Deller.
In their hypothesis, Deller and his team combine known knowledge about the brain to form a theory of human thinking. The theory begins with the Nobel's discovery of two types of cells in the brain of rodents, which were later discovered in humans. Both types of cells demonstrate a similar activity that forms the animal's self-awareness in space - for example, when eating. It turned out that the joint activity of these cells makes it possible to form a mental map of the space around, which is preserved and renewed during subsequent actions.
A similar picture of the work of cells can be observed in humans, and, which is important, not only when navigating in space. The same cells are active when learning new concepts, as evidenced by a 2016 study. In this work, the volunteers learned to associate photographs of birds, which differed only in the length of their neck and legs, with different symbols, such as a tree or a bell. A bird with a long neck and short legs was associated with a tree, while a bird with a short neck and long legs belonged to the bell. Thus, a particular combination of bodily attributes became a symbol.
In a subsequent memory test, the volunteers indicated whether the birds were associated with one of the symbols. Interestingly, the entorhinal cortex was activated in much the same way as during navigation, providing our thoughts with a kind of coordinate system. This allows scientists to argue that the course of human thought can be viewed as a path through different mental dimensions.
“These processes are especially useful for behaving in situations in which we have never been. For example, if a person has already met a tiger, lion or panther, but has never seen a leopard, he would define it as part of the concept of "big cat", since it is already saved on his mental map, "says Jacob Bellmund), co-author of the study.
Dmitry Mazalevsky
Promotional video: