Very often, people take so-called proactive actions without even thinking about it. For example, when a person behind the wheel presses the gas pedal a moment before the yellow traffic light turns green, or starts tapping out the rhythm of a familiar melody a moment before it starts playing in the playlist.
In such cases, people rely, on the one hand, on the experience gained in the past, stored in memory, and on the other, on a sense of rhythm. Our brain uses the so-called temporal patterns to predict when an event will occur. Accordingly, this allows you to concentrate attention on it and perform certain actions.
Moreover, the "predictive contexts" can be different. For example, in the example with a traffic light, a person knows in advance a specific time interval between two events (changing signals), and in the case of listening to a melody, he knows in advance its rhythm.
In the course of the new work, scientists from the University of California at Berkeley proved that the human brain has two "chronometers" at once, each of which is responsible for one of the two tasks described above. Moreover, the corresponding groups of neurons are located in different regions of the brain.
Together with his colleague Richard Ivry, he proposed a new interpretation of a key process in our life - calculating when to take an action. According to the authors of the work, the presence of two different systems helps a person not only to be aware of himself at a particular moment in time, but also to understand what will happen in the next moment.
In the course of their work, the scientists examined the predictive abilities of people with Parkinson's disease and cerebellar degeneration. It should be clarified that in the first case, there is a violation of the functions of the basal nuclei, whose neurons are activated during concentration. And the cerebellum is responsible, among other things, for the coordination of movements.
Experts conducted an experiment to compare how well such patients can manipulate the concept of time, focus and take actions, depending on temporal signals.
Promotional video:
Participants from both groups were shown a very simple sequence: red, white and green squares appeared in front of them on the monitor screen in turn. The task was to press the button when a green square appears on the screen. The appearance of a white square in this case should have been a warning signal.
In the first test, colored squares appeared at regular intervals. It turned out that patients with impaired cerebellar function respond better to rhythmic signals and coordinate actions than participants with Parkinson's disease.
In another test, the time intervals between the red and green squares changed, that is, there was no definite predetermined rhythm. In this case, patients with Parkinson's disease did better.
Obviously, in patients with cerebellar degeneration, the perception of non-rhythmic signals is impaired, while in patients with dysfunction of the basal nuclei, on the contrary, the perception of rhythmic signals is impaired.
It is logical to assume that the brain engages two different mechanisms of "timing out", which challenges existing theories, the authors of the work note.
According to him, the knowledge about which mechanisms fail in certain neurodegenerative disorders is very important. With this data, scientists will be able to develop new strategies for helping patients to improve their interaction with the world around them.
Actually, the authors of the study have already put forward a hypothesis that it is possible to improve the work of "neural chronometers" without pharmaceutical preparations. In their opinion, this will be helped by special computer games or applications for gadgets that are aimed at stimulating certain areas of the brain. It is possible that virtual reality technology can also be used for therapy.
More details about this work and its results are described in an article published in the journal Proceedings of the National Academy of Sciences.
Yulia Vorobyova