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Study shows: Why scratching and itching also have an infectious effect


Scratching: itching is as contagious as yawning
When other people start laughing, you often have to participate. And yawning is also contagious. It is similar with itching. Researchers have now found out why you have to scratch yourself when you see others doing it. It obviously has nothing to do with empathy.

Itching is very contagious
Be it because of tiredness or boredom: If we see someone who yawns with courage, we can hardly suppress our own yawning. According to experts, the emotional closeness we feel towards a human being plays an important role. That's why yawning people who are close to us is much more infectious than strangers. Itching is also contagious, but empathy does not play a role here, as researchers have now found out.

No form of empathy
"Itching is very contagious," said Zhou-Feng Chen of the Washington University School of Medicine in St. Louis. "Sometimes it is enough to just mention itching and you start scratching yourself." So far, it has not been entirely clear why.

"Our experiments show that it is a predisposition and not a form of empathy," said the study author in a message.

The researchers have now published the results they achieved with mice in the scientific journal Science.

Try mice
The team of scientists showed one mouse in a locked room videos of another mouse scratching.

"Within a few seconds, the mouse in the enclosure started scratching itself," Chen said.

“It was very surprising because mice are known for their poor vision. They use smell and touch to explore the area, so we didn't know if a mouse would notice a video. Not only did she see the video, but she could also see that the mouse was scratching it. ”

Innate and instinctive behavior
The researchers also found that a certain area of ​​the brain is particularly active when scratching, which also controls falling asleep and waking up.

At the same time, a substance was released in this region, which the scientists had identified in previous work as one of the main messengers for the transmission of itching signals between the skin and spinal cord.

"The mouse sees no other mouse scratching and then thinks it could scratch," Chen said. Rather, the brain starts sending out signals.

So this is not a form of empathy. The expert assumes that the animals cannot control the contagious itching behavior. "It's innate behavior and instinct," Chen said. (ad)

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