How does alcohol cause blackouts? - Shannon Odell

翻译人员: Jacky He 校对人员: suya f.

In 1969, Dr. Donald Goodwin gathered a group of study participants

1969 年，

唐纳德·古德温 (Donald Goodwin) 博士召集了一组研究参与者

and asked them each to recall the object he'd shown them two minutes prior.

要求他们每位回忆他在 两分钟前向其展示的物体。

The twist?

暗含条件？

All the participants were very intoxicated.

所有参与者都烂醉如泥。

Despite this, most could pay attention to the task

尽管如此，大多数人 仍可专注于任务，

and correctly name the toy they had just seen.

正确回忆起他们 刚才见到的玩具。

Yet, when Donald asked them to recall that object a mere 30 minutes later,

不过，仅在 30 分钟后， 当唐纳德要求他们回想那个物体时，

half the participants drew a blank,

有一半的参与者显得迷茫，

having “blacked out” the earlier moment entirely.

因为他们在前一刻“失忆”了。

This study illustrates the strange and somewhat selective effects

这项研究说明了

alcohol has on the brain.

酒精对大脑特定性的奇怪影响。

Many intoxicated people can perform complex tasks

许多醉酒的人可以执行复杂的任务，

like holding a detailed conversation or navigating a walk home.

例如进行详细的对话 或步行回家。

Yet for those experiencing what is known as a blackout,

然而，对于那些经历所谓 记忆空缺 (blackout) 的人来说，

the memory of these events is quickly forgotten.

这些事件的记忆 会被快速地遗忘。

So how does alcohol cause these memory lapses?

那么酒精是如何导致 这些记忆力减退的呢？

First, let's identify the culprit.

首先，让我们认出罪魁祸首。

While a single drink often contains hundreds of different chemical compounds,

虽然一杯饮料通常含有 数百种不同的化合物，

ethanol is responsible for alcohol's effects on the brain.

乙醇是酒精对 大脑影响的主要原因。

Ethanol is lightweight and lipophilic,

乙醇质轻且具有亲脂性，

meaning its structure easily dissolves into fats,

这意味着其结构 很容易溶解于脂肪，

like those in the membranes of the outer blood-brain barrier.

例如血脑屏障的外层膜。

Once inside the brain, ethanol’s unique structure

乙醇进入大脑后，其独特的结构使其

allows it to bind to, interact, and affect many different neuronal receptors,

与许多不同的神经元 受体结合、相互作用与影响，

impairing pathways that allow you to make careful decisions, control your impulses,

从而损害使你谨慎选择、 理性决策，和调节运动的

and even manage your motor skills.

神经通路。

And the networks that control memory seem to be especially sensitive

控制记忆的网络 似乎对酒精

to alcohol’s effects.

特别敏感。

Typically, information about your surroundings is taken in

通常，有关周围环境的信息

by your sensory organs and sent to the brain.

由你的感官 接收并输送到大脑。

Neurons transfer this information to one another

神经元之间通过

via chemical messengers called neurotransmitters,

神经递质的化学媒介 传递这类信息，

which are released by one neuron and received by receptors at another.

由单个神经元释放， 并结合于另一个神经元的受体。

When a neurotransmitter binds to a receptor,

当神经递质与受体 结合时，

it unlocks an internal channel, allowing small ions to flow into the cell.

它会解锁内部通道， 允许离子流入细胞。

If enough ions enter the cell, the neuron fires,

如果有足够的离子进入细胞， 神经元就会激活，

sending the signal forward.

向前发送信号。

Through this process, different regions of the brain

通过这个过程，大脑的不同区域

can communicate with one another in milliseconds,

可以在几毫秒内相互交流，

creating our moment-to-moment understanding of the world.

从而产生我们对世界实时的理解。

But ethanol interacts with receptors,

但是乙醇会与受体相互作用，

making it harder for neurons to communicate.

使神经元难以工作。

While compromised, the brain is still able to transfer information,

尽管受到抑制， 大脑仍然能够传输信息，

which is why many intoxicated people seem somewhat capable

这就是为什么许多醉酒的人 似乎有一定能力执行基本

of performing basic tasks.

任务的原因。

In other words, brain function is highly impaired,

换句话说，大脑功能严重受损，

but not completely broken.

但并未完全瘫痪。

But memory storage is a different story.

但是记忆存储是另一回事。

The transfer of moment-to-moment understanding

普遍认为，将实时的信息

to something we can remember is thought to depend on a process

转化为某种记忆的过程取决于一个

called long-term potentiation, or LTP.

名为长期增强的过程，即 LTP。

LTP happens throughout the brain,

LTP 在整个大脑中进行，

but is especially important in learning and memory regions,

但对于学习和记忆区域 尤其重要，

like the neocortex and the hippocampus.

像新皮层和海马体。

During LTP,

在 LTP 过程中，

the firing of a neuron triggers physical changes to its structure.

神经元的激活会导致 其结构的形态变化。

For example, more receptors may be moved to the cell's surface,

比如，更多的受体 可能会附于细胞表面，

making the neuron more sensitive to future signaling from its neighbors.

从而使神经元对未来的 临近信号更为敏感。

These physical changes increase the likelihood that a cell

这些物理变化增加了细胞

will fire again at that connection,

再次建立此连接的可能性，从而

strengthening the wiring between neurons.

巩固了神经元之间的连接。

And through this stronger connection,

通过这种更牢靠的联系，

it's thought that a stable memory is formed.

稳定记忆便会出现。

Yet studies suggest that ethanol has a unique ability to disrupt LTP,

不过，研究表明乙醇具有 对付 LTP 的独特能力，

blocking the physical changes needed for memory formation.

阻止记忆形成 相关的物理变化。

So, while moment-to-moment information is encoded and understood,

因此，虽然瞬时信息被 编码和处理，

the storage of that information is blunted,

它们的存储被弱化，

resulting in a blackout.

从而导致“暂时失忆”。

Of course, not all levels of drinking result in blackouts.

当然，并非每次饮酒 均会导致晕厥。

They happen when the concentration of alcohol in the blood, or BAC,

当血液中的酒精浓度， 即 BAC 超过约 0.16 的水平时，

exceeds a certain level, approximately 0.16.

这种情况便会发生。

But there’s no magic number.

但是没有明显的界限。

At slightly lower BACs, brownouts, or the spotty memory of events, can occur,

BAC 较低时，也许会 精神不佳，记忆欠缺，

as some neurons continue to function properly while others fail.

因部分神经元正常工作， 而其余的失效。

And drinking too much can cause a person to pass out altogether.

饮酒太多则会导致 一个人彻底晕厥。

Other factors like dehydration level, genetic differences, medications,

其他因素，例如饮水量、 遗传特征、服用药物

and even how much you’ve eaten can affect the likelihood of a blackout.

甚至吃的多少， 也会影响失忆的概率。

And teenagers appear to be especially vulnerable

而青少年由于 其大脑的快速增长，

due to the substantial changes in brain development during those years.

最容易受影响。

Alcohol’s short-term effects usually don’t last longer

醉酒的短期症状不会超过

than the time it takes for their body to metabolize it, or about a day.

人体代谢酒精的时间， 即大约一天。

But repeatedly over-drinking can damage neurons and permanently impair memory.

但是，多次过量饮酒会损害 神经元，并永久损伤记忆力。

It can also harm other organs like the liver,

它还会伤害其他器官，像肝脏，

which works overtime breaking down alcohol.

超负荷地运作以分解酒精。

After all, experiencing a blackout or witnessing others

另外，经历失忆，或看到他人

in this compromised state

处于这种状态中，

can be a lot for your mind and body to process.

将为你的心灵与身体带来负担。