科学详解：大脑以为你中毒了所以你晕车了?

Traveling makes us feel sick because modern transport tricks the brain into thinking we have been poisoned, a neuroscientist has said.

一位神经系统科学家表示，现代交通工具会诱导大脑认为我们已经中毒，所以旅行常常使我们感到不舒服。

Being in a car, train, boat or plane causes conflicting signals in the brain which trigger a reaction similar to that which occurs when someone is poisoned.

乘坐汽车、火车、船舶或飞机的体验会在大脑中形成相互矛盾的信号，这会引发和人们中毒时相似的反应。

Dr Dean Burnett, of Cardiff University, said the feeling of nausea is caused because the brain thinks the body needs to remove a toxin through vomiting.

卡迪夫大学的迪安•伯内特博士称，大脑认为人体需要通过呕吐排毒，于是便造成了这种恶心感。

But in fact, the 'poisoning' effect is caused by the mixed messages from the muscles – which tell the brain the body is motionless – and the ears, which sense movement.

但事实上，这种“中毒”效应是由肌肉中的混合信息所引发的，肌肉向大脑传达身体静止的信息，而耳朵却察觉到身体在运动。

Speaking on the US radio show Fresh Air, Dr Burnett said that the body had not yet evolved to cope with the sensation of being in vehicles, where the body is being moved without performing movements itself.

伯内特博士在美国广播电台节目《新鲜空气》中表示，在交通工具中人们的身体在被移动，而本身却未执行任何行动，人体还未进化到能够适应这种感觉。

He said: 'When we're in a vehicle like a car or a train or a ship especially, you're not actually physically moving... Your muscles are saying 'we are stationary'.

他说：“当我们乘坐尤其是汽车、火车或是轮船这样的交通工具时，你的身体事实上没有在运动，因此你的肌肉也认为‘我们是静止的’。”

'If you are sitting in a ship, you're looking at a static environment, so there's no information for the eyes to say 'we are moving'.

“如果你坐在船上，你是看着一个静态的环境，因此并没有传递给眼睛‘我们正在运动’的信息。

'But the fluids in your ears, they obey the laws of physics. And they are sort of rocking around and sloshing because you are actually moving.

“但是你耳朵里的液体遵循物理定律，你确实在移动，因此它们四处摇摆、晃动。

'So what's happening there is the brain's getting mixed messages. It's getting signals from the muscles and the eyes saying "we are still" and signals from the balance sensors saying 'we're in motion'. Both of these cannot be correct. There's a sensory mismatch there.

“所以问题就是大脑得到了混合信息。肌肉和眼睛告诉它‘我们是静止的’，而从平衡感知器官传来的信号又说‘我们在运动’。这两者不可能同时正确，所以知觉就不相匹配。

'And in evolutionary terms, the only thing that can cause a sensory mismatch like that is a neurotoxin or poison. So the brain thinks, essentially, it's been being poisoned.

“从进化角度来看，唯一能够引起感知矛盾的就是神经毒素或中毒，因此大脑判断其根源在于中毒了。

'When it's been poisoned, the first thing it does is get rid of the poison, aka throwing up.'

“当中毒的时候，首先要做的就是排毒，也就是呕吐。”

He explained that reading in a car made the sensation of travel sickness worse, because the eyes were focused on a small, static space and gave the brain no information to explain that the body was moving.

他进一步解释，在车上阅读会恶化晕车的症状，因为眼睛始终盯着一块小而静止的空间，让大脑无从解释为什么感到身体正在移动。

The feeling of sickness could be relieved by looking out of a car window because this showed the brain movement was taking place.

看车窗外却能够缓解晕车的感觉，因为这告诉大脑人体正在运动当中。

'You can see the passage and movement itself, so that balances the system,' he said.

他说：“你可以亲眼目睹过道以及移动本身，这也就让系统得到了平衡。”

'The brain's going: 'Oh, look, things moving - I must be moving' - and then sort of calms down the sickness response.'

“大脑这样思考：‘噢，看，物体在运动，我也一定在运动’——这也就在某种程度上缓解了晕车的反应。”

Dr Burnett, who was discussing his new book 'Idiot Brain: what your head is really up to', said brain systems became more refined and efficient as people aged but that children were more susceptible to travel sickness because their brains were still developing.

伯内特博士在新书《愚蠢的大脑：你的头究竟怎么了》中说道，随着人们岁数的增大，脑部系统变得越来越精炼和高效，而孩子们更容易晕车，因为他们的大脑仍在发育当中。

He said there was no clear reason why some people suffered from travel sickness more than others, calling it a 'quirk of development'.

他表示，现在还无法清楚地解释为什么有些人比别人更容易晕车，他将其命名为“发育中的怪异现象”。

But he said there were several other aspects of modern life with which the brain had not yet evolved to cope.

但他同时声称，大脑进化至今还未能适应现代生活中的好多其他方面。

For example, jet-lag was the brain's response to being disorientated by being moved between time zones with different levels of daylight, he said.

他说，举例来说，时差综合症是人体穿梭于不同时区不同白昼时，大脑因感到迷乱而产生的反应。

Vocabulary

slosh: 搅动，晃动

aka: 又叫作，亦称(also known as)

jet-lag: 时差综合症