American neurologists have understood why patients who have one of their hemispheres removed do not become idiots.
Neurologists at the California Institute of Technology performed MRI scans of the brains of 6 patients who had one of their hemispheres removed during childhood. Removed to cure especially severe epilepsy. Those who underwent such a difficult operation - hemispherectomy - did not become mentally retarded.
According to study leader Dorit Kliemann, the interaction with these patients does not raise any suspicion that they have only half of the brain. The cognitive abilities of the operated are normal, they lead a normal life. MRI scans and gave an answer to the question "Why?"
Physicians examined 6 patients with removed hemispheres - right and left.
Neurologists point out in a report published in the journal Cell Reports - briefly referred to by the ScienceAlert portal - that the reason for the phenomenon lies in the brain's amazing ability to restore lost connections and compensate for the activity of lost areas by connecting others. Scientists, of course, guessed about this. But now we are convinced. So in people who have lost half of their brains, a new and very strong neural network was formed - more extensive than usual. As a result, the remaining half began to work like a whole brain. At least the activity she observed was similar to that usually displayed by the whole brain.
It turns out that for normal life, half the brain would be enough for us. Why then do you need a whole? And so complicated too? And so voluminous - 1.2 liters on average? And 0.75 would be enough. There are no answers. By the way, scientists do not yet know how new connections appear in the brain to replace the lost ones.
NOT FOR THE FIRST TIME
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Woman at 24 found out that she had no cerebellum
NewScientist magazine told about a Chinese woman who lived for 24 years without arousing suspicion that she was missing something in her brain. The shortage was discovered by doctors (Chinese PLA General Hospital of Jinan Military Area Command in Shandong Province), to whom the woman turned with a complaint of dizziness. And the fact that she is seasick when walking - as if seasickness begins.
The patient's mother reported that the girl began to walk late - only at the age of 7, and began to speak normally at the age of 6.
Doctors placed the woman in a CT scanner. Scan showed: she has no cerebellum. And, apparently, never was. Where it should be is an empty space.
Woman without cerebellum (above), below is a scan of the brain with the cerebellum.
The cerebellum is an important part of the brain. It resembles it in form and structure. Located under the hemispheres. This department is even called the small brain. He is responsible for coordination of movement, a sense of balance, muscle tone. A person with a slight damage to the cerebellum walks like a drunk. Or like a sailor on the deck of a ship that is heavily heaving. Cannot get a finger to the specified point.
In case of severe damage, a person cannot not only walk or stand, but even sit. In general, it is simply impossible to live without the cerebellum. Nevertheless, the woman succeeds. Another miracle of adaptation. Doctors believe that the cerebellar functions are taken over by the cerebral cortex.
Almost without brains, but with cerebral fluid
Maybe women have such a brain that they do not notice the absence of any part of it? Not at all. The stronger sex is even more amazing in this sense. For several years naad in France, a 44-year-old man was identified, who had only a small part of his brain - a thin layer adjacent to the skull. The rest of the volume is filled with liquid.
“He's missing about three-quarters of his brain,” said Lionel Feuillet, a neurologist at the Mediterranean University in Marseille, France, who described his observations in The Lancet, which NewScientist referred to.
A man with fluid instead of a brain (left pictures), on the right is a normal brain structure.
The shortage, again, was revealed by accident - after a man came to the clinic with complaints of weakness in his left leg. They made a tomogram. And they saw that there was almost no brain.
During the examination, it turned out that in infancy, the patient suffered from hydrocephalus - just from the fluid in the head, for which a drainage tube was installed to pump it out. She was removed when the guy was 14 years old. But the liquid, as it turned out, accumulated again. And it seemed to dissolve most of the brain.
Surprisingly, the minimum of brain and fluid in the head did not bother the patient. And those around him did not notice anything strange in his behavior. In IQ tests, a man scored 75 points with an average rate of 100. He works in the service sector, is married and has two children.
The brain never ceases to amaze.
VLADIMIR LAGOVSKY