In birds and some aquatic mammals, the left and right hemispheres of the brain can sleep alternately. Until now, it was believed that people are not capable of such a trick. However, as scientists managed to find out, on the first night in a new place in the hemispheres of our brain they sleep asynchronously.
“Often a person falls asleep at a new place. Scientists studying sleep in laboratories even discard data obtained on the first night of research, considering these results to be atypical, ”says Yuka Sasaki, a psychologist at Brown University.
Sasaki and her team are interested in how a person’s sleep in a new place proceeds. The results of their work were published in the journal Current Biology on April 21.
As it turned out, in the slow phase, the neuroactivity of the left hemisphere, in contrast to the right, was less consistent with the state of sleep. Scientists suggest that the left half of the brain on the first night in a new place does not sleep as deep as the right. However, starting from the second night, the imbalance disappears, and both hemispheres sleep equally deeply.
In the human brain there is a so-called network of passive mode of operation. It is a multitude of nerve cells that are active at a time when the brain is not busy with a specific task. Just a network of passive mode of operation was active in the left hemisphere during sleep.
Researchers reproduced harsh sounds near the ears of sleeping volunteers. At the same time, it was possible to establish that the network of the passive mode of operation of the left hemisphere reacted faster in the event of silence violation. When the sounds were played near the right ear, from where the signals come to the left hemisphere, the volunteers woke up significantly faster. Interestingly, this effect was most pronounced during the first night in a new place.
During one night, the brain goes through a phase of slow sleep several times. However, the Sasaki experiment covered only the first of these cycles. Therefore, scientists do not yet know whether the left hemisphere keeps "vigilance" throughout the night. To find out, Sasaki and her group are preparing new research.
“In this sleep mode, there is a sense, at least in the animal world. Sleep is useful if the risks with which it is associated do not outweigh its benefits to the body. Safety during sleep can often be maintained, just without losing sight of what is happening around. Obviously, a similar "night watch" acts not only on the first night in a new place. For example, a mother can sleep soundly even during a thunderstorm, but wake up from the child's faint whimpers, ”explains Jerome Siegel, who studies sleep at the University of California.
The article is based on materials .
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