In a minute we can take a look with a camera, so if I just set that up now as we're coming here.
马上我们就能通过镜头看到了，让我把摄影机架好吧，我们要到了。
I grab this monitor?
我拿着监视器吗？
Yeah, you can take the monitor.
对，你可以拿着。
Okay.
好的。
You should hopefully, as I go under the water now, start to see one or two of the sea squirts.
让我把它放下水，现在你应该看到一两只海鞘了。
Oh, yes!
啊，真的有！
Let's go further down, and you can see one there right now in the light.
再深点，你现在能看到另一个，就在光照的地方。
Oh, yes, now I can see.
看到没？
Can you see it?
看到了吗？
Yes.
嗯看到了。
Close-up.
来个特写。
Yeah, and there's more here.
对，这里还有很多。
There we are.
在这。
Yes.
没错。
But what on Earth does a sea-squirt have to do with the way cannabis affects the human brain?
但为什么这些海鞘和大麻一样，对大脑产生影响呢？
Well, if we go back say 500 million years ago to the oceans that would have been full of creatures like these,
如果我们回到5亿年前的大海，你就能看到到处都是这种生物，
before there were fish and animals with backbones in the sea.
那时候没有鱼和脊椎动物。
We would find living in the oceans thriving, creatures such as these sea-squirts, that we find here on the marina today.
我们会发现在海洋里面繁盛的生物，比如今天我们这里看到的海鞘。
And they have, within them, very simple nervous systems that operate in much the same way that our nervous systems operate.
它们的神经系统都很简单，工作原理和我们神经系统很相似。
In all animals, the nervous system is made of the same components - large numbers of nerve cells carrying electrical signals...
所有动物的神经系统的构成都是相同的，大量的神经细胞携带着电信号...
And wherever these cells meet, the signal is passed from one cell to a receptor in the next cell, by a chemical messenger called a neurotransmitter.
在细胞接触的地方，信号从一个细胞发出，被另一个细胞的接受器接受。这种传递，通过一种叫神经传递素的化学信使实现。
Across the brain there are different types of these neurotransmitters, such as dopamine and serotonin.
大脑中，有种类各异的神经传递素，例如多巴胺和5-羟色胺。
All animals from fish to donkeys to humans have inherited this basic structure.
所有的动物，从鱼到驴子到人类，都继承了这种基本结构。
But way back in time, the sea squirt evolved an innovation to this system.
但在远古，海鞘的神经系统出现了革命性的进化。
What happened was the nervous system acquired a new chemical, a chemical if you like that had a new flavour, a new type of chemical.
神经系统获得了一种新的化学物质，它散发一种或许你会喜欢的新味道。一种新类别的化学物质。
And it's this chemical that is related in structure and a similar shape to the chemical that's found in cannabis.
正是这种化学物质，在结构和形状上与四氢大麻酚非常相似。
