Sleepy life
"An unprecedented combination of past impressions". What is that?
"An unprecedented combination of past impressions" is what the famous Russian physiologist Ivan Sechenov once called our dreams. This image reflects well one important feature of dreams. It is impossible to see in a dream what was not once accepted by our brain.
While sleeping in our brain can come to life, only something that once left its own trace in the nerve cells of the brain can come to light in the form of a bright picture. Figuratively speaking, while sleeping, the consciousness can take out of the storeroom what has ever been put there. It is impossible to take from this pantry what is not there. It is well known that the blind from birth do not dream of visual images.
Yes, in a dream you can see only what was in the dream. But in what form?
A man sees sometimes absolutely fabulous, incredible dreams. There is something that does not happen in a dream! We see ourselves in our childhood, traveling to different countries, fighting, meeting dead people without surprise, talking to animals like in fairy tales, flying through the air
In the brain of a sleeping person, like in a movie, in a short time, sometimes the whole human life passes. And no matter how fantastic the pictures unfold in a dream, they seem authentic, real.
So what's a dream like?
Our distant ancestors once had a strong belief in this regard: during sleep, the human soul temporarily leaves his body to wander the world; we dream about what it sees in its travels.
Many primitive tribes had a strict custom: it is impossible to wake a sleeping man. He will wake up, and his soul may not have time to return. American Indians consider it deadly dangerous to paint a person's face when he sleeps. Why? Returning, the soul may not recognize its place of stay, will fly by and a person dies without waking up. The science of sleep cannot boast of its age. Essentially, scientists have only been doing brain research for the last hundred years.
What is a dream?
Until recently, the answer to science was as follows: sleep is the rest of the nerve cells of the cerebral cortex. To be more precise, it is a process of protective inhibition, a fascinating cell - the neurons of the cortex and gradually spreading to deeper parts of the brain.
At the same time neurons stop responding to the irritation signals coming to them. Thus, cells of the cerebral cortex were recognized responsible for sleep (and dreams). And only. New research scientists have revealed a more complex picture.
Back in the 30's the famous Soviet scientist P.K. Anokhin, while studying the work of the brain, expressed the idea: along with cortical cells and subcortical parts of the brain participate in the mechanism of sleep. Studies have shown that this is the case. This was discovered when scientists began to study in detail the work of individual parts of the brain, including those under large hemispheres.
Researchers were particularly interested in the so-called reticular formation, or reticular formation in the brain stem. It was established that as soon as the brain stem is separated from the large hemispheres, the animal (experiments were conducted on higher animals) is immersed in a restless sleep. It became clear that it was here, in the brain stem, that some mechanism is working to organize our sleep.
To be continued in the next part https://zen.yandex.ru/profile/editor/id/5d9330af8600e100b06bbabe/5d94945005fd9800b1aa0dd1/edit