What happens when you remove the hippocampus? - Sam Kean

当你移除海马组织会发生什么? - 山姆·基恩

翻译人员: Siyun Zhou 校对人员: Francis Ma

On September 1st, 1953,

在 1953 年，9 月 1 日

William Scoville used a hand crank and a cheap drill saw

威廉·斯科维尔使用 一个起动手柄和一个廉价电钻

to bore into a young man's skull, cutting away vital pieces of his brain

在一个年轻男子的头骨上钻孔 切除了他脑部的重要部分

and sucking them out through a metal tube.

并且用金属管子把它们吸走

But this wasn't a scene from a horror film or a gruesome police report.

但是这并不是恐怖电影场景 或者一个可怕的警察报告

Dr. Scoville was one of the most renowned neurosurgeons of his time,

斯科维尔医生是那时候最有名 的神经外科医生之一

and the young man was Henry Molaison, the famous patient known as "H.M.",

这位年轻男子是亨利·莫莱森 被熟知为「H.M.」的有名病人

whose case provided amazing insights into how our brains work.

他的病例为我们了解大脑如何运作 提供了神奇的认识

As a boy, Henry had cracked his skull in an accident

儿时，亨利在一次意外中 撞裂了他的头骨

and soon began having seizures, blacking out and losing control of bodily functions.

很快他开始癫痫发作，昏迷 和丧失控制身体的能力

After enduring years of frequent episodes, and even dropping out of high school,

在常年出现这种经常偶发性发作， 甚至高中退学后

the desperate young man had turned to Dr. Scoville,

这个绝望的年轻人找到了 斯科维尔医生

a daredevil known for risky surgeries.

一个因冒险手术而闻名的敢干的人

Partial lobotomies had been used for decades to treat mental patients

部分前脑叶白质切除术 常年用于治疗精神患者

based on the notion that mental functions were strictly localized

理论基础是大脑功能是严格局部化

to corresponding brain areas.

于相应大脑区域的

Having successfully used them to reduce seizures in psychotics,

曾成功使用它们减少精神病患者发作

Scoville decided to remove H.M.'s hippocampus,

斯科维尔决定移除 H.M. 的海马组织

a part of the limbic system that was associated with emotion

它是人脑边缘系统的一部分 与情感相关

but whose function was unknown.

但是具体功能仍然不清楚

At first glance, the operation had succeeded.

刚开始，手术成功了

H.M.'s seizures virtually disappeared, with no change in personality,

H.M.的发作几乎消失了 和个人性格没有改变

and his IQ even improved.

而且他的智力甚至提高了

But there was one problem: His memory was shot.

但是很快出现了一个问题： 他的记忆被打乱了

Besides losing most of his memories from the previous decade,

除了失去他早年的大部分记忆

H.M. was unable to form new ones, forgetting what day it was,

H.M. 不能形成新的记忆 他会忘记日期

repeating comments, and even eating multiple meals in a row.

重复说话，甚至连续吃很多顿饭

When Scoville informed another expert, Wilder Penfield, of the results,

当斯科维尔通知其他专家 结果，韦尔德·潘菲尔德

he sent a Ph.D student named Brenda Milner to study H.M. at his parents' home,

派了他的博士学生布伦达·米尔纳 在亨利父母家研究 H.M. 的情况

where he now spent his days doing odd chores,

H.M. 现在整天做奇怪的事

and watching classic movies for the first time, over and over.

重复看经典电影

What she discovered through a series of tests and interviews

她发现通过一系列的测试和访谈

didn't just contribute greatly to the study of memory.

不仅对记忆研究产生巨大贡献

It redefined what memory even meant.

它重新定义了记忆的内涵

One of Milner's findings shed light on the obvious fact

米尔纳的其中一个发现 透露了明显的事实

that although H.M. couldn't form new memories, he still retained information

虽然 H.M. 不能够形成新的记忆， 他仍然保留信息

long enough from moment to moment to finish a sentence or find the bathroom.

足够长时间来完成一个句子 或者找到浴室

When Milner gave him a random number,

当米尔纳给他一个随机数字

he managed to remember it for fifteen minutes

他使用15分钟记住它

by repeating it to himself constantly.

通过经常重复这个数字

But only five minutes later, he forgot the test had even taken place.

但是仅仅五分钟后， 他忘记这个测试曾经发生过

Neuroscientists had though of memory as monolithic,

神经科学家曾想过记忆是整体的

all of it essentially the same and stored throughout the brain.

所有记忆大体一样 而且保存在整个大脑中

Milner's results were not only the first clue for the now familiar distinction

米尔纳的结果并不是第一个 得出现在相似的

between short-term and long-term memory,

关于长期记忆和短期记忆区别的线索

but show that each uses different brain regions.

但是展示了每个记忆使用大脑不同区域

We now know that memory formation involves several steps.

我们现在知道记忆的形成涉及很多步骤

After immediate sensory data is temporarily transcribed by neurons in the cortex,

在瞬间感受数据在大脑皮层 被神经元短暂转录

it travels to the hippocampus,

它传递到海马组织

where special proteins work to strengthen the cortical synaptic connections.

在那里通过特殊蛋白质加工来加强 皮质突触连接

If the experience was strong enough,

如果经历足够强烈

or we recall it periodically in the first few days,

或者我们间歇性地 在前几天经常回忆

the hippocampus then transfers the memory back to the cortex for permanent storage.

海马组织会把记忆传递回去大脑皮层 形成永久存储

H.M.'s mind could form the initial impressions,

H.M. 的大脑可以形成首要的印象

but without a hippocampus to perform this memory consolidation,

但是没有海马组织进行记忆巩固

they eroded, like messages scrawled in sand.

他们逐渐毁坏 就像信息乱写在沙上

But this was not the only memory distinction Milner found.

但是这并不是米尔纳发现的唯一记忆分区

In a now famous experiment, she asked H.M. to trace a third star

在一个当今闻名的实验中

她要求H.M.在两个星星的线条空隔间 临摹出第三个星星

in the narrow space between the outlines of two concentric ones

while he could only see his paper and pencil through a mirror.

但他只可以通过镜子看到他的纸和笔

Like anyone else performing such an awkward task for the first time,

像其他所有第一次进行 这个尴尬任务的人一样

he did horribly.

他做得很糟糕

But surprisingly, he improved over repeated trials,

但惊讶的是，他在重复尝试后进步了

even though he had no memory of previous attempts.

甚至虽然他并没有之前尝试的记忆

His unconscious motor centers remembered what the conscious mind had forgotten.

他的无意识运动中心记忆了 意识大脑忘记的信息

What Milner had discovered was that the declarative memory of names, dates and facts

米尔纳发现关于名字、日期 和事实的陈述性记忆

is different from the procedural memory of riding a bicycle or signing your name.

和关于骑自行车或者签自己名字的 程序性记忆不同

And we now know that procedural memory

而且我们现在知道程序性记忆

relies more on the basal ganglia and cerebellum,

依赖更多基底神经节和小脑

structures that were intact in H.M.'s brain.

这些结构仍然保留在H.M.的大脑中

This distinction between "knowing that" and "knowing how"

「懂得那样」和「懂得怎样」的区别

has underpinned all memory research since.

从此成为了所有记忆研究的基础

H.M. died at the age of 82 after a mostly peaceful life in a nursing home.

H.M.在82岁时安详地卒于疗养院

Over the years, he had been examined by more than 100 neuroscientists,

这些年来，他被多于100位 神经科学家研究

making his the most studied mind in history.

使他的大脑成为历史上 最多人研究的大脑

Upon his death, his brain was preserved and scanned

当他死亡的时候，他的 大脑被保存和扫描

before being cut into over 2000 individual slices

然后被切成多于2000块 独立的切片

and photographed to form a digital map down to the level of individual neurons,

并且被照相来生成一个细致到 神经元个体级别的电子图

all in a live broadcast watched by 400,000 people.

过程全部现场直播并且有40万群众观看

Though H.M. spent most of his life forgetting things,

尽管H.M.花费大半生在忘事

he and his contributions to our understanding of memory

但他和他对人类了解记忆的贡献

will be remembered for generations to come.

会被每一代人永记