Why do people’s eyes move when they sleep?

Recently, scientists have learned a lot about sleep and what the brain is doing at this moment. For example, we managed to find out what and how people remember in a dream. However, until the last moment, it was not known thoroughly why people make eye movements in their sleep. This occurs during REM sleep. It occurs immediately after the phase of non-REM sleep and lasts 10-15 minutes. It is at this moment that we have the most clear and vivid dreams, which we sometimes even remember when we wake up. Previously, it was assumed that a person at this moment follows with his eyes those objects that move in front of him in a dream, but there was no evidence for this. In a recent study, scientists from the University of California at San Francisco managed to find out exactly what is associated with eye movement.

Eye movements in a dream – what are they connected with?

Previously, scientists have conducted rather primitive studies that tried to explain why people move their eyes during REM sleep. They simply recorded eye movements and then woke the person up and asked what they were dreaming about. For example, if he saw an object that moved from left to right, then his eyes should have moved from left to right.

However, in order to be able to compare eye movements with dreams, the latter must be vivid and well remembered, which is not so often the case. At the same time, a person should tell about the smallest details that he remembers. If some events are mixed up, then the study is not accurate. In addition, it is practically impossible to compare the movement of the eyes at a certain point in time with an event in a dream, because a person cannot say exactly how many seconds or minutes ago he dreamed of an object that he followed with his eyes.

Dreams are difficult to compare with events in dreams

Moreover, in dreams, the situation and events change very quickly, so eye movements seem chaotic. From this we assume that eye movements are not associated with observing objects in a dream, but with random muscle contractions. Accordingly, all work in this area did not have any serious evidence base.

REM sleep and eye movement

Researchers at the University of California at San Francisco decided to conduct the study in a more precise way. They monitored the electrical activity of the brain and compared it with eye movements. But how can the electrical impulses of the brain be correlated with eye movements?

Before, it was really impossible. Recently, however, scientists have discovered neurons in the thalamus that determine the position of the head relative to the body. Therefore, they were called “compass”. But what about eye movements? The fact is that the movement of the eyes and the movement of the head are closely related. What do you do when, for example, you look at a person passing by or a passing car? Follow him not only with your eyes, but also with your head.

Eye movements are associated with the “compass” neurons of the brain

Scientists also found that these neurons work not only during wakefulness, but also in sleep. From this we can conclude that these neurons are responsible for the position of the head during dreams, when the head actually lies motionless.

I must say that all the same mechanisms work in animals. When an object catches their attention, they look in its direction and turn their head. At the same time, all mammals also have two phases of sleep, and they move their eyes during the fast phase.
Therefore, the researchers conducted their study on mice.

People follow with their eyes the objects they see in their dreams.

First, the authors determined which electrical signal corresponds to which position of the head and eyes. To do this, they compared the signals with the eye movements of an awake mouse. The scientists then conducted the same study on a sleeping mouse. It turned out that “compass” neurons in sleep are also interconnected with eye movements, as well as during wakefulness. They report this in the publication Skinse.

Now, in fact, it can be argued that during REM sleep, our eyes move for the reason that we, as in life, follow the various objects that surround us. Although, there is one catch – it is not known whether mice dream in the same way as people. However, some experts suggest that dreams are dreamed not only by animals, but even by spiders, which we talked about earlier. But, in any case, in order to finally put an end to this issue, scientists will have to conduct a similar study on humans.