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The medical drama "Dr. House" depicts a police officer who lost his sight after being injured.

The policeman did not feel that he could not see. When the doctor asked him what the other doctor was wearing, he replied without hesitation: "dark blue pants, white shirt, black shoes." It's like I really saw it. However, the doctor in front of him was dressed in a completely different costume.

No matter how the doctor explained, the police officer was still sure that he could see it and felt that he was all right. The doctor said that physically his eyes could see yes, but the problem was that the brain could not process the information properly.

The plot is fictional, but a similar phenomenon does exist in the real world. When blind people do not think they are blind, their symptoms may be attributed to Anton syndrome (Anton's Syndrome).

The disconnection between brain regions as early as the first century AD, the ancient Roman philosopher Lucius Annaeus Seneca mentioned a case. A slave suffered from acute blindness, but after that she did not admit that she was ill, always complaining that "the room was too dark" and kept asking for a change of dormitory.

Now we know that this is probably a form of anosognosia (anosognosia), in which patients may have cognitive impairment of the disease because of brain damage. However, I am afraid that the ancients more than two thousand years ago could not look at this problem scientifically and systematically.

Until the end of the 19th century, a psychiatrist named Gabriel Anton (Gabriel Anton) in Austria encountered a special patient. Ursula Mercz, a 56-year-old former tailor who often had dizziness and headaches, was later found to be mentally abnormal, and her mental state affected her work. Ursula had been unable to work for two years before Dr. Anton received the doctor.

During the treatment of Ursula, Dr. Anton found that she was sometimes seeing things with a very narrow field of vision, and on the same day, the only field of vision could turn into a whole dark patch. As the disease progressed, the patient soon became completely blind (although the pupil response and fundus examination were still normal). At this time, she could no longer detect light or dark, could not perceive objects near or far away, and even if someone suddenly moved towards her, Ursula's eyelids did not move.

What puzzled doctors was that throughout the process, patients did not seem to realize that they were losing or had lost their vision-Ursula never complained that his eyes could not see, nor did he express how his life had been affected. When the doctor put some objects in front of her and asked Ursula what it was, she would calmly say that she had seen it, and that the descriptive objects were always different from reality. Sometimes the doctor didn't put anything, and she said she saw it. When asked how she felt about her eyesight, Ursula replied in general terms: just like that, I was better when I was young.

Photo source: if pixabay says that mental retardation or blurred consciousness causes patients not to know they are blind, it doesn't seem to make sense in Ursula. After all, she complains about other troubles, such as trying to say the name of something but often says it wrong or can't remember it, and Ursula expresses it. In other words, she felt her language barrier, but she didn't know she was visually impaired.

In the end, Ursula, whose condition worsened, died in a long coma. Dr. Anton finished his work as the patient's attending doctor, but his task as a neuroscientist is not over. He cut open Ursula's brain to find out which area was wrong, causing the patient to lose his vision.

Overall, the patient's brain did not atrophy severely. However, in the cerebral cortex, the occipital lobe (occipital lobe), which is mainly responsible for processing visual signals, has pathological changes in the subcortical white matter, resulting in a large loss of white matter. There was a similar situation in the left and right occipital lobes. Some of the occipital gyrus (occipital gyri) were damaged, even the angular gyrus (angular gyrus) at the junction of the occipital lobe and the parietal lobe.

In the eyes of Dr. Anton, symmetrical lesions in the occipital lobe are associated with blindness in Ursula. She could not see that it was not the eyes themselves that were damaged, but the brain's ability to process visual signals.

You may have noticed that it is not enough to rely on the eyes to see the flowers and plants in the world. As a light sensor, the eye is only responsible for collecting light, which is converted into neuronal signals, and then processed by specific brain regions, will become a landscape that we can enjoy. If the sensor is intact and the brain area that processes the signal fails, the person will not have normal vision, which is also called "brain visual impairment".

It is not uncommon for humans to be blinded by brain damage, but that does not explain why Ursula thought he could see it. Scientists are more concerned about whether there is a normal connection between the visual areas of Ursula's brain and other brain regions.

So Dr. Anton began to observe some of the pathways in the patient's brain. He found that many of the pathways connecting the occipital lobe to other lobes were cut off, the connection between the visual cortex and its surroundings was cut off, and the connection between the left and right occipital lobes was also cut off. If the visual area does not work properly, and other brain regions do not get the news of "visual area failure", it may make sense that it is difficult for patients to perceive their blindness.

However, scientists are still not quite sure which area of the brain damage is responsible for the disease.

"because I don't wear glasses." when Dr. Anton showed Ursula objects, she would reach out to touch objects placed nearby, and she would just guess or "fabricate" answers to objects placed in the distance. In any case, she doesn't think she's blind.

Scientists suspect that even if the connection between the visual cortex and the surrounding area disappears, it can still accept stimuli from other regions. For example, researchers have found under a microscope that there are enough pathways to transfer stimulation from the temporal lobe to the visual center. But whether this kind of stimulation will be regarded as real vision is not clear from the case of Ursula.

In addition to Ursula, Dr. Anton has encountered other patients who are unable to perceive their own diseases. For example, a 69-year-old milker who did not feel deaf appeared with Ursula in a paper published in 1899. By the early 20th century, a French neuroscientist named Joseph Babinski had a name for this phenomenon, called anosognosia, in which patients had no knowledge of a particular sensory or functional defect.

Visual agnosia, later known as Anton syndrome (Anton's Syndrome), can also be called Anton-Babinski syndrome (Anton-Babinski Syndrome). The disease is still rare, and the most common cause is ischemic stroke that damages both occipital lobes.

These blind patients, like Ursula, are unable to correctly answer what is in front of them. But when they are declared wrong, they often deny their blindness by saying "the light is too dim" or "I don't wear glasses".

However, some patients may be luckier than Ursula. Since Anton syndrome usually occurs after cerebrovascular accidents, the treatment is mainly to protect the safety of blood vessels, such as controlling blood pressure, blood sugar and blood lipids, etc., plus standard drug treatment such as aspirin or statins. Young patients are usually able to recover without significant impairment in cognitive function, language or memory.

Reference:

Https://academic.oup.com/book/12735

Https://eyewiki.aao.org/Anton_Syndrome

Https://www.ncbi.nlm.nih.gov/books/NBK560626/

Https://owenlab.uwo.ca/pdf/1993-David-COGNITIVE%20NEUROPSYCHOLOGY-An-annotated-summary-and-translation.pdf

This article comes from the official account of Wechat: global Science (ID:huanqiukexue)

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