Epiphany Point

Scientists have long suspected that the blind can see. And it's only now that I've figured out why this is happening.

An elderly man moves along the corridor with slow steps. From his uncertain movements, you can guess that he is completely blind. No one helps the man, and this walk is about to end in a fall—right in his path is a wastebasket. At the very last moment, the blind man takes a step to the side and clumsily walks around this object. And then another, a large cardboard box in the middle of the aisle. The man does not even touch the obstacle.

This amateur camera video appeared on the Internet two years ago, and thousands of people have watched it. From the outside it looks like a staging, but in fact, a serious scientific experiment. It was held by the famous Belgian psychologist Beatrice de Gelder. She did not disclose the name of the hero of the video. In her work, he goes by the initials TN. The man is indeed blind, at least in the usual sense of the word. Many years ago, this man suffered several severe strokes at once. They damaged the area of ​​the brain responsible for vision. Since then, TN has seen nothing but solid darkness.

It is not ordinary vision that helps a man to bypass obstacles, but something completely different. And he's not the only person with this ability. Scientists call this phenomenon "blind vision". They have known about it for more than a hundred years, but only now have they finally figured out why this is happening. Last week, American neurophysiologist Michael Schmid published the results of his study. He managed to find a new area in the brain that independently processes the signal coming from the eyes. By teaching people to use their hidden abilities, scientists will be able to partially restore the ability to see to the blind. You can't really call them blind then.

BLIND SEARCH

Scientists first encountered “blindsight” during World War I, when thousands of people with head wounds began to arrive at hospitals. Scottish neurophysiologist George Riddoch worked in one of these military hospitals. He drew attention to a very strange thing: the soldiers who received severe damage to the visual area of ​​\u200b\u200bthe brain did not completely go blind. Many of the wounded reacted to quick movements, such as a wave of the hand.

After 24 years, a similar effect was observed by the famous German neurophysiologist Heinrich Klüver. He, however, did not work with people, but with monkeys. The scientist personally removed the areas of the brain responsible for vision from them, but the primates still continued to respond to the movements of the scientist. For example, they blinked when he suddenly showed them an object.

At the suggestion of Kluver, scientists started talking about "blind vision" seriously. True, not all—there were critics. Klüver's monkeys continued to see the world with their most ordinary vision, they said, the scientist did not destroy the brain of his charges deep enough. "Blindsight" was finally recognized only recently. “For that, we all have modern brain-scanning techniques to thank,” Dutch neuroscientist Rainer Goebel tells Newsweek.

He took a direct part in the war with the skeptics. It was Goebel who scanned the brain of a TN patient on a tomograph and proved that the areas responsible for vision were indeed damaged. Then Goebel and Beatrice de Gelder suggested that some other part of the brain allows the patient to bypass obstacles.

THE BASIC INSTINCT

Scientists are amazed not only by the rare abilities of the TN patient. The fact is that the blind overcome obstacles instinctively. “When TN first walked around all the objects in the corridor, we rushed to congratulate him,” de Gelder tells Newsweek. “He was very embarrassed, it seemed to him that he was just walking in a straight line all the time.” TN believed the scientists only after the experiment was repeated so many times. “But his wife was not surprised at all,” recalls de Gelder. “She had long noticed that her husband was moving suspiciously carefully around the rooms.”

Another patient with "blindsight" visited de Gelder's laboratory—he, too, was unable to explain what it was he was able to "see." The researcher showed him images of people—calm and somehow frightened. Sensors were connected to the patient's face to record muscle activity. The blind man swore he couldn't see anything, but the instruments said otherwise. Each time a picture of a frightened person appeared on the screen, the subject's face would involuntarily twitch. He, too, was getting scared. “There is one thing I want to understand more than anything in the world,” says Goebel.

The scientific work of the American Michael Schmid can answer this question. For the first time, he was able to accurately pinpoint the region of the brain responsible for "blind vision." Now, few people will be surprised that such people act unconsciously - this part of the brain is rather primitive. Schmid's experience was cruel, and therefore he worked not with humans, but with monkeys. First, the researcher repeated the work of the German Klüver and removed the areas of the brain responsible for the ability to see. The monkeys lost their normal vision, but continued to respond to the images.

Schmid displayed a contrasting image (a combination of black and white cells) on the monitor, and the primates immediately began to move their eyes over it. All this time, the animal's brain was scanned by a tomograph. The device pointed to a particularly active part of the brain, it was in an area called the thalamus. Biologists have long known that it is involved in signal transmission from the eyes to the center responsible for image processing. Schmid proved that the thalamus is not just an intermediate link and is quite capable of working independently. When a scientist turned off a part of the thalamus in monkeys with a special drug, they immediately lost the ability to "blind vision." Their eyes stopped moving across the screen.

“This is a very important result for medicine,” Schmid rejoices. “Now it’s clear how the brain is able to at least partially restore the ability to see.” Rainer Goebel also believes that blindsight research is primarily useful for doctors. With their help, you can make the life of patients a little easier. “I am absolutely sure that this ability can be developed,” he says. “At first, such patients do not believe in themselves, but then they get used to it, and they do everything very well.”

Schmid is convinced that "blind vision" is constantly working in healthy people. “The fact is that the image comes from the eyes to the thalamus very quickly,” the scientist explains. “It is logical to assume that this type of vision can be turned on in critical situations when a person does not have time to think.” For example, this can happen while driving during an emergency. The driver has not yet had time to understand anything, and his foot is already pressing on the brake.

To prove this, the researcher needs to conduct more than one experiment. But Schmid is not going to move on to experiments on humans in the near future - it is not so easy to find participants for experiments. “In the world, only a few studies have been carried out on scanning the brains of people with “blind vision,” the scientist complains. “And the TN patient, as I understand it, is now busy in another laboratory.” Apparently, TN will be busy for a very long time. “He is a doctor by training, and he does not need to explain that our results can help other people. That is why TN agrees to work with us,” says de Gelder.

Anton Stepnov, Polina Eremenko