…and they do it without the participation of consciousness.
Our brain instantly receives a huge amount of information, which does not remain in a shapeless heap. For every event we can tell when and where it happened. Thanks to the knowledge of “when” and “where” we connect different events, objects, feelings, etc. with each other. By organizing information, we are able to predict the future – in the sense that we know, for example, that after a red traffic light there is a yellow one, followed by a green one, and that if we press a switch in the wall, the light in the room will turn on.
Organizing information, building chains of events, describing the circumstances of place and time must occur in their own way at different levels of brain organization. Researchers at the University of California, Los Angeles have shown how this happens at the neuronal level. Experiments were carried out with people who had electrodes inserted into their brains due to epilepsy (we have talked many times about such patients who, for medical reasons, undergo specific brain surgery and who simultaneously participate in neuropsychiatric research). The electrodes read the activity of neurons in different areas of the brain, including the hippocampus and entorhinal cortex, one of the main centers of memory. They also help us navigate in space and time – again, we wrote a lot about the navigation cells of the hippocampus and the time cells of the entorhinal cortex. The lion’s share of all incoming information passes through these parts of the brain, since a lot of what happens to us must, at least for a short time, linger in memory.
In the experiment, volunteers with electrodes were shown portraits of different people while recording neural activity. As a result, it was possible to isolate individual neurons that responded specifically to a particular picture. That is, for example, when a photo of a man in dark glasses appeared, the activity of one neuron, which ignored all other pictures, increased extremely; in the photo of a woman in a hat, the activity of some other neuron increased, etc. Then the same faces began to be shown in a certain order.
This order is most conveniently described by a triangle, in which experimental pictures were located at the vertices and on each side, and they were now shown so that each picture was followed by one of its immediate neighbors. That is, for the photo that is located at the vertex of the triangle, they showed a photo from one of the sides that converges to this vertex, but not photos from other vertices – after all, they are not immediate neighbors, between the photos at the vertices of the triangle there is a photo on its sides. The photos on the sides were also connected with lines, so that it turned out to be another small triangle, which added to the neighborhood relationship. It is worth clarifying that the triangles only describe the order of alternation of photos – the participants in the experiment did not see any triangles, photographs simply appeared in front of them.
Alternation of photos in the experiment: after photo 1 there was photo 2 or 3, but not 4, not 5 or 6, because these photos were in no way adjacent to photo 1. (Illustration by Nature)
Eventually, neurons in the hippocampus and entorhinal cortex began to learn the order of the photos—that is, they began to respond not only to “their” photo, but also to those that were their neighbors in the order of alternation. For example, the “man in dark glasses” neuron began to respond to a woman in a hat and a man with a beard, because one of them always came after the man in dark glasses. But at the same time, the same “man in dark glasses” neuron did not react to the doctor’s photo, because the doctor was not a neighbor in the triangular pattern. Most importantly, the experiment participants themselves were not aware of any pattern – they could not describe the order of the photos when they were directly asked to do so. While the pictures were being shown, they were even deliberately distracted by questions about what they saw in the photos, so that they could not think about whether there was any pattern in the alternation of photographs. In an article in Nature it is said that in the intervals between tests, the neurons themselves, without pictures in front of their eyes, played a sequence of images, as if reinforcing the learned material.
We are quite aware of things like traffic lights, but everything has “where” and “when” circumstances, even the smallest events. It is probably quite natural that consciousness is freed from awareness of the huge mass of such material. New data will certainly help to understand some psychological phenomena; Perhaps in the future we will have memory enhancement tools that target precisely this ability of neurons to pick up patterns in a sea of information in the background.
By the way, quite recently we wrote about a similar skill of hippocampal neurons – that they combine objects according to certain characteristics. But that study was not so much about the temporal sequence of images as about abstract associations and categories; although, of course, temporal sequence may well be a criterion for creating an abstract association.
Source: www.nkj.ru
