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Ah, hiccups. We've all been there.
我们都打嗝。
Usually, they're no big deal – unless you're one of the 4,000 Americans admitted to the hospital every year for hiccups,
通常，打嗝不是什么大事—除非你是那4000个每年因打嗝而住进医院的人之一，
or you're that Iowa farmer who hiccuped for 68 years straight. Still, even the occasional bout of hiccups can be annoying.
或者你就是那个连续打了68年嗝的爱荷华农民。不过，即便是偶尔的打嗝也会令人恼火。
And as you hold your breath or gulp down water to try to make them stop, you may wonder: Why is this happening to me?
当你想屏住呼吸或大口喝水时，试着停止打嗝时，你可能会想：为什么会打嗝？
Well… scientists don't really know. But teeny little baby hiccups might provide a clue.
其实科学家们也不知道。但是小婴儿打嗝可能会提供线索。
Hiccups mainly involve the diaphragm (that dome-shaped muscle below your lungs that drives your breathing)
打嗝主要涉及膈肌（肺下驱动呼吸的穹顶状肌肉）
and the glottis (the opening between your vocal cords).
和声门（声带之间的开口）。
Basically, they occur when your diaphragm spasms, causing you to rapidly inhale. That forces your glottis to audibly slam shut.
当你的膈肌痉挛，导致你快速吸气时，你就会打嗝。这会迫使你的声门砰地一声关上。
And everyone experiences them at some point — they're one of the first things we do in the womb.
每个人在某个时候都会打嗝—打嗝是我们在子宫里做的第一件事。
Fetuses begin hiccuping at just nine weeks old.
胎儿在只有9周大的时候就开始打嗝。
And they continue to hiccup a ton (between 8 and 14 times per hour!) until they're about 24 weeks old.
并且他们会继续打嗝（每小时8到14次！）直到他们长到大概24周的时候为止。
Then, things settle down somewhat. Though, young babies still hiccup a bunch, especially if they were delivered early.
然后事情稍微稳定下来。尽管如此，小婴儿还是会打嗝，尤其早产儿。
For example, preterm newborns (those born before 37 weeks) spend an average of 15 minutes a day hiccuping!
例如，早产儿（37周之前出生的）平均每天打嗝15分钟！
Which got scientists at University College London thinking that there might be a developmental purpose behind all this convulsing.
英国伦敦大学学院的科学家就在想，打嗝可能是出于发育的目的。
So for a study published in December 2019, they outfitted 13 newborns with a cute cap of electrodes and monitored their hiccups.
因此，在2019年12月发表的一项研究中，他们给13名新生儿戴上一顶可爱的电极帽，并监测他们打嗝的情况。
They found that every time a baby's diaphragm contracted, it triggered two large brainwaves, then a third brainwave.
他们发现婴儿每一次的膈肌收缩都会触发两个大脑波，然后是第三个脑波。
The third wave is the most interesting, because it looks similar to the brainwave created when we hear a noise.
第三个波最有趣，因为它看起来很像我们听到噪音时产生的脑电波。
So, the researchers think the babies may be hearing the "hic" and connecting it in their brains with the sensation of their diaphragm contracting.
所以研究人员认为婴儿们可能听到打嗝声并在大脑中将这个声音和他们膈肌收缩的感觉联系在一起。
This may allow their brains to form neural circuits which help them sense what's happening with their internal organs.
这或许让他们的大脑形成了神经回路，帮助他们感知内部器官的变化。
The fancy scientific term for this ability is interoception, and it's how you know you're having trouble breathing,
这种能力的科学术语是内感受，指的是你如何知道自己的有呼吸困难
or your stomach feels full, or your heart is beating fast.
或者你的胃感觉很饱，你的心跳很快。
Creating these nerve connections between the brain and the diaphragm could also help them learn to control their breathing.
创造这些大脑和膈肌之间的神经联系也可以帮助他们学会控制呼吸。
The same scientists think something similar happens when fetuses kick in the womb.
同一组科学家认为胎儿在子宫里踢腿时也会发生类似的事情。
Basically, those kicks may help them create mental maps of their bodies so they can sense where their legs are,
踢腿或许可以帮助他们在脑海中勾画出自己的身体，这样他们就能感知自己的腿在哪，
and, eventually, learn to make voluntary movements.
最终学会做一些随意的动作。
So why do adults hiccup if our brains don't need to learn how to breathe anymore? That's a good question.
所以如果你的大脑不再需要如何呼吸，那么成年人为什么还会打嗝呢？这是个好问题。
It could simply be that we can't get rid of this reflex after it's served its purpose. But who knows?
这可能只是因为我们无法在它发挥作用后摆脱这种反射。但是谁知道呢。
There aren't a whole lot of studies of run-of-the mill occasional hiccuping in adults since,
没有很多关于成人偶尔打嗝的研究，
well, it's not really something doctors are concerned about.
因为这并不是医生真正关心的事情。
So maybe if scientists investigated hiccups more, they'd find these spasms have a weirdly amazing purpose in adults, too.
如果科学家们对打嗝进行更多的研究，他们可能会发现这些痉挛在成年人身上也有一个奇怪而神奇的作用。
Thanks for asking about hiccups, Michelle and Anne! And thanks in general to all of our patrons on Patreon.
感谢米歇尔和安妮的提问！感谢我们的赞助人。
We have the most wonderfully nerdy community of supporters! If you'd like to join them, you can learn more at Patreon.com/SciShow.
我们有最优秀的支持者。如果大家想加入他们，可以去Patreon.com/SciShow了解更多。
And if you're already a patron and have a weird question like this about how the world works, drop it in our QQ inbox!
如果你是我们的赞助人，如果你也有一些奇奇怪怪的问题，请向我们提问吧！
We not only read those questions, we make some of them into videos like this one. So your question could be next!
我们不仅会看这些问题，我们还会将一些问题制成视频。下一个可能就是你的提问！
