what? Scientists say we have a second brain in our intestines !

为了生存和发展，人类吃的食物种类多到令人咂舌，居住地不同，饮食也迥然各异。而这都取决于我们强大的消化系统，它复杂到甚至有自己的大脑！快来看一下我们神奇的消化系统究竟是如何工作的吧！

Ultimately, the credit for that flexibility goes to our digestive system. The complex human gut can process the milk and meat of other animals, cooked and raw combinations of foods, and a wide variety of plants — be them fermented, roasted, dried, salted or something else. The system that manages the physical and chemical breakdown of foods, the extraction of nutrients from them, and the efficient ejection of waste is so complex that it turns out it even has its own brain. And as Giulia Enders, a German writer and scientist, explains in her TEDTalk above, there's a lot more to know. But we are making progress on that front.

从根本上来说，我们之所以能灵活地选择食物要归功于我们的消化系统。人类复杂的肠道可以处理其他动物的乳汁和肉、熟食和生食杂烩以及各种各样的植物——不论它们是经发酵、烤制、烘干、盐渍，或是其他方式制作的。消化系统能对食物进行物理性和化学性分解、从中提取营养物质以及有效排出废弃物，它复杂到甚至有自己的大脑。正如德国作家兼科学家Giulia Enders在她的TED演讲中解释的那样，还有更多需要了解的。但我们正在这方面取得进展。

The Enteric Nervous System (ENS) is a collection of over 500 million neurons — the most found outside the big, main brain that lives in your skull. It probably evolved before our other main brain did; it's ancient hardware.

肠道神经系统(ENS)是一个拥有5亿多个神经元的集合体——除头骨大脑外，这是神经元分布最多的地方。肠道可能在我们的另一个主要大脑之前就已经演化； 它是古老的身体硬件。

Where is the ENS? Well, it's in every part of your gut, lining your esophagus, down into your stomach, throughout your intestines large and small, and all the way to the (ahem), end. Instead of a singular lump of an organ, it's more like a mesh that's integrated into the whole system. The ENS has all sorts of neurotransmitters zipping around, sending chemical signals from one part of the gut to another. (In fact, the same neurotransmitters as are found in the brains in our skulls.) It's not conscious like our main brain is, but without it, we couldn't survive. However, the ENS will still function even if we are otherwise brain dead or damaged.

ENS在哪儿？ 其实，它在你肠道的每一个部分，始从食道、下达胃部、穿过大小肠，一直到（嗯哼）终点（此处指尿道等部分）。它更像是一个集成到整个系统中的网格，而不是一个单一的器官。ENS有各种各样的神经递质快速移动，从肠道的一端向另一端发送化学信号。（事实上，这里的神经递质和我们头骨大脑中的神经递质一模一样。）它不像我们的主脑那样有意识，但没有它，我们就无法生存。 然而，即使我们脑部死亡或损坏，ENS仍然在起作用。

Scientists have known about the ENS, but didn't really know how it worked until recently. According to a new study published in JNeurosci, they've figured it out. Using mice, the scientists were able to observe a "novel pattern of rhythmic coordinated neuronal firing" — basically the neurons in the ENS coordinated with each other to move muscles around the large intestine that in turn physically moved pellets through the mice guts. Without the mouse having to think "I want to digest this," the pellets were digested.

科学家已经知道ENS，但直到最近才真正知道它是如何工作的。JNeurosci发表的一项新研究表明，他们已经找到了答案。 科学家们以小鼠为实验对象，观察到了一种“节奏性协调神经元移动的新模式”——ENS中的神经元基本上会相互协调，以便使大肠肌肉蠕动，从而使颗粒（小鼠食物）通过小鼠大肠来消化。小鼠没有“我想消化这个”的想法，但是这些颗粒依然被消化了。

Yes, our bodies have plenty of automatic functions, but this is different. The gut isn't governed by the central nervous system (CNS), though it does communicate with it via the vagus nerve. The ENS operates independently. It can exchange information with the the CNS, but it doesn't need it to digest food. This is part of the reason we don't have to eat at the same time each day, or continuously. The system is always "on," but it isn't actively working until we eat. This "smart system" in our gut allows digestive movement to occur only when it's needed — and now we know how that happens.

是的，我们的身体有很多自动功能，但这是不同的。虽然肠道通过迷走神经与中枢神经系统（CNS）沟通，但肠道不受CNS的支配。ENS独立运作。它可以与CNS交换信息，但它不需要CNS的指挥就能消化食物。这是我们不必每天、或连续同时进食的原因之一。该系统始终处于“开启”状态，但在我们吃东西之前它不会积极的工作。我们肠道中的这种“智能系统”仅在需要消化活动时才会起作用——现在我们知道发生了什么。

Interestingly, the scientists also observed that in between digestions, there was still "ongoing activity" in the ENS. What was it doing? We have no idea. There's obviously plenty more to learn about the ENS, but knowing that it causes digestion in the way it does advances our understanding of both digestion and the capacities of this second "brain."

有趣的是，科学家们还观察到，在两次消化之间，ENS仍然存在“正在进行的活动”。它在做什么？我们不知道。显然，我们对ENS相关知识的了解仍有很大的探索空间，目前仅知道它消化的方式提高了我们对消化和第二个“大脑”能力的理解。

Holistic health advocates have long suggested a brain-gut connection. We already know that 90 percent of the serotonin our body makes (often called the "happy chemical") is produced in special cells in the GI tract. Half of the dopamine we make is located there, too. Both serotonin and dopamine have a physiological function and also influence mood when they make their way out of the gut and into the blood stream. Connecting the dots between the known function of those neurotransmitters, it's possible the ENS could act in a more direct way to influence our emotions and state of mind, though this has yet to be understood fully by scientists.

全面健康倡导者长期以来一直认为大脑与肠道是相联系的。我们已经知道90％的人体血清素（通常被称为“快乐化学物质”）是由胃肠道中的特殊细胞产生的。我们人体的一半多巴胺也位于那里。血清素和多巴胺都具有生理功能，并且当它们从肠道进入血流时也会影响情绪。通过连接这些神经递质的已知功能之间的点，ENS以更直接的方式影响我们的情绪和精神状态是有可能的，尽管科学家尚未完全理解这点。

All of this is not only food for thought, it reminds us that "going with your gut" when it comes to decisions might not be such a brainless way to make choices after all.

所有的这些不仅发人深思，它还提醒我们，在做决策时“跟随你的直觉”（gut既有‘肠道’的意思，也有‘直觉’的意思）可能并非毫无头脑。