BBC雙語(yǔ)：你為什么怕?lián)习W癢的原因找到了！

Why are we ticklish?

人怕?lián)习W癢的原因

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Professor Sukhi Shergill, Psychiatry and Systems Neuroscience, King's College London

蘇基·謝吉爾 倫敦大學(xué)國(guó)王學(xué)院精神病學(xué)與系統(tǒng)神經(jīng)科學(xué)教授

Tickling: love it, or hate it? Or even a bit of both... It's a strange phenomenon.

“被人撓癢癢這種感覺(jué)：你是喜歡還是討厭?或者都有一點(diǎn)… 這是個(gè)奇怪的現(xiàn)象。”

There are two types of tickling sensation. Knismesis - a mildly annoying feeling caused by light movement like this. And there's gargalesis- which is caused by a deeper pressure on your skin.

癢的感覺(jué)分為兩種：“觸覺(jué)癢”指由這種輕撫的動(dòng)作引起的輕微不適感;“逗笑癢”是通過(guò)給皮膚施加更強(qiáng)的力道而引發(fā)的。

When your skin is touched, the nerve endings underneath send electrical signals to the brain. We laugh when we're tickled because the sensation is picked up in two areas of the brain at once - the part which analyses touch, but also the part that creates pleasure.

當(dāng)你的皮膚被觸碰時(shí)，皮下的神經(jīng)末梢會(huì)向大腦傳送電子信號(hào)。我們被人撓癢癢之后會(huì)發(fā)笑，因?yàn)檫@種感覺(jué)會(huì)同時(shí)出現(xiàn)在大腦的兩個(gè)區(qū)域中：分析觸覺(jué)的區(qū)域，以及產(chǎn)生愉悅感的區(qū)域。

But of course, being tickled isn't always enjoyable.

當(dāng)然，被撓癢癢并不總是件令人感到愉快的事情。

In fact, it also affects the part of the brain that makes you feel panic in the face of danger.

事實(shí)上，它還會(huì)影響大腦中使你臨危恐慌的部分。

So, strange as it may seem, laughing when you're tickled could be a sort of primitive defence mechanism - giving a signal to show our submission to a predator.

所以，雖然看起來(lái)很奇怪，但被胳肢后大笑可能是一種原始的防御機(jī)制，就好比是身體通過(guò)發(fā)送信號(hào)來(lái)展現(xiàn)對(duì)捕食者的順從。

So, why can't we tickle ourselves? We think it's to do with the brain's cerebellum that monitors our movement. It can tell the difference between expected and unexpected sensations. In other words, it already knows what you're doing and is too clever to react.

那么，為什么不能胳肢自己呢?我們認(rèn)為這和小腦有關(guān)，小腦負(fù)責(zé)監(jiān)控身體的運(yùn)動(dòng)。它能區(qū)分預(yù)期和意外的感覺(jué)之間有何不同。換言之，它已經(jīng)知道你在做什么，只是因?yàn)樘斆鞫蛔鞒龇磻?yīng)。

詞 匯

tickling sensation

癢的感覺(jué)，發(fā)癢

nerve endings

神經(jīng)末梢

electrical signals

電子信號(hào)

defence mechanism

防御機(jī)制、防衛(wèi)表現(xiàn)