Can we edit memories? | Amy Milton

Transcriber: Joseph Geni Reviewer: Camille Martínez

譯者: Ellie Siu 審譯者: Helen Chang

Memory is such an everyday thing that we almost take it for granted.

記憶是日常生活中的一部分， 我們總是把它視為理所當然。

We all remember what we had for breakfast this morning

我們都記得早餐吃了什麼，

or what we did last weekend.

或者上週末做了什麼。

It's only when memory starts to fail

只有當記憶力開始衰退的時候，

that we appreciate just how amazing it is

我們才會感激它是如此神奇，

and how much we allow our past experiences to define us.

和反思我們如何讓 過去的經歷來定義自己。

But memory is not always a good thing.

但是，記憶不一定是好事。

As the American poet and clergyman John Lancaster Spalding once said,

就如美國詩人和牧師 約翰·蘭開斯特·史佩爾丁曾說過：

"As memory may be a paradise from which we cannot be driven,

「記憶可以是天堂， 在那裡我們不會被驅趕；

it may also be a hell from which we cannot escape."

記憶也可以是地獄， 在那裡我們無法逃脫。」

Many of us experience chapters of our lives

大多數人經歷過某些人生的章節，

that we would prefer to never have happened.

希望它從未發生過。

It is estimated that nearly 90 percent of us

估計我們當中大概大概有 90% 的人

will experience some sort of traumatic event during our lifetimes.

在一生中會經歷造成創傷的事件。

Many of us will suffer acutely following these events and then recover,

大多數人在這些事件之後 會非常痛苦，然後恢復，

maybe even become better people because of those experiences.

甚至因為這些經驗 而變成更好的人。

But some events are so extreme that many --

但是有些事件過於極端——

up to half of those who survive sexual violence, for example --

例如半數經歷過性暴力的人——

will go on to develop post-traumatic stress disorder,

會出現創傷後壓力症候群，

or PTSD.

又稱為 PTSD。

PTSD is a debilitating mental health condition

PTSD 是一個會導致 心理健康衰弱的疾病，

characterized by symptoms such as intense fear and anxiety

特徵是強烈恐懼和焦慮感、

and flashbacks of the traumatic event.

和經常回想起當時的情境等症狀。

These symptoms have a huge impact on a person's quality of life

這些症狀對人們的生活品質 有著重大的影響，

and are often triggered by particular situations

通常在特定的情況和環境下

or cues in that person's environment.

會引發這些症狀。

The responses to those cues may have been adaptive when they were first learned --

第一次發作後 人會習於自己所做的反應

fear and diving for cover in a war zone, for example --

——例如在戰場上撲向掩護地點——

but in PTSD,

但是 PTSD 的患者

they continue to control behavior when it's no longer appropriate.

仍受制於這些已不必要的行為。

If a combat veteran returns home and is diving for cover

有返家的退伍軍人因嚴重的焦慮，

在聽到汽車的火爆聲時 仍會撲向掩護地點，

when he or she hears a car backfiring

or can't leave their own home because of intense anxiety,

或無法離開家門。

then the responses to those cues, those memories,

那麼這些反應、記憶，

就成了我們所謂的適應不良。

have become what we would refer to as maladaptive.

In this way, we can think of PTSD as being a disorder of maladaptive memory.

PTSD 可被稱做 記憶適應不良的疾病。

Now, I should stop myself here,

現在，我必須暫停一下，

因為我彷彿是在說記憶是單一的。

because I'm talking about memory as if it's a single thing.

It isn't.

它不是。

There are many different types of memory,

人類有很多不同種類的記憶，

and these depend upon different circuits and regions within the brain.

它們取決於腦內不同的迴路和區域。

As you can see, there are two major distinctions in our types of memory.

如你所見，

我們的記憶類型有兩個主要區別。

There are those memories that we're consciously aware of,

首先是我們有意識的記憶。

我們知道自己有這個記憶，

where we know we know

and that we can pass on in words.

並且可以用文字表達。

This would include memories for facts and events.

這包含資訊、事件等記憶。

Because we can declare these memories,

因為我們可以描述這些記憶，

we refer to these as declarative memories.

我們稱它們為陳述性記憶。

The other type of memory is non-declarative.

另一種記憶是非陳述性記憶。

These are memories where we often don't have conscious access

對於這些記憶，

我們無法意識到記憶的內容，

to the content of those memories

and that we can't pass on in words.

並且無法用文字表達。

The classic example of a non-declarative memory

非陳述性記憶最經典的例子是

is the motor skill for riding a bike.

騎自行車的運動技能。

Now, this being Cambridge, the odds are that you can ride a bike.

在劍橋，你多半會騎自行車，

You know what you're doing on two wheels.

知道如何安坐在那兩輪之上。

But if I asked you to write me a list of instructions

但是如果我叫你列出指令

that would teach me how to ride a bike,

教我怎麼騎自行車——

as my four-year-old son did when we bought him a bike

就像我在兒子四歲生日時， 買給他腳踏車那樣——

for his last birthday,

you would really struggle to do that.

你會感到非常困難。

How should you sit on the bike so you're balanced?

要如何坐才能讓單車平衡？

How fast do you need to pedal so you're stable?

要踏多快才能平衡？

If a gust of wind comes at you,

如果一陣風吹過，

which muscles should you tense and by how much

你該用哪些肌肉出力多少

so that you don't get blown off?

才不會被風吹倒？

I'll be staggered if you can give the answers to those questions.

如果你能回答出這些問題， 我會感到非常的吃驚。

But if you can ride a bike, you do have the answers,

如果你會騎腳踏車， 你一定知道答案。

you're just not consciously aware of them.

你只是沒有意識到它們而已。

Getting back to PTSD,

回到 PTSD，

another type of non-declarative memory

另一種非陳述性記憶

是情緒的記憶。

is emotional memory.

Now, this has a specific meaning in psychology

在心理學，

它指的是我們對環境線索

and refers to our ability to learn about cues in our environment

and their emotional and motivational significance.

以及情感與動機的學習能力。

What do I mean by that?

那是什麼意思呢？

Well, think of a cue like the smell of baking bread,

想想看，線索就像是 烘烤麵包的香味，

or a more abstract cue like a 20-pound note.

或者更抽象的話， 一張 20 磅的紙幣。

Because these cues have been pegged with good things in the past,

因為這些線索會與美好的回憶相連，

we like them and we approach them.

因此我們喜歡並會接近它們。

Other cues, like the buzzing of a wasp, elicit very negative emotions

其他線索，例如黃蜂的嗡嗡聲，

某些人會做出誇張的逃避行為。

and quite dramatic avoidance behavior in some people.

Now, I hate wasps.

我討厭黃蜂。

I can tell you that fact.

我可以告訴你這個事實。

But what I can't give you are the non-declarative emotional memories

但是，我無法解釋 附近有黃蜂時我的反應。

for how I react when there's a wasp nearby.

一種非陳述性情緒記憶。

I can't give you the racing heart,

你無法感受到我的心跳加速、

the sweaty palms, that sense of rising panic.

流滿汗水的手掌和恐慌感。

I can describe them to you,

我能形容，

but I can't give them to you.

但你無法感受。

Now, importantly, from the perspective of PTSD,

重要的是自 PTSD 的角度

stress has very different effects on declarative and non-declarative memories

壓力對陳述性和非陳述性記憶

and the brain circuits and regions supporting them.

以及大腦回路和區域有不同的影響。

Emotional memory is supported by a small almond-shaped structure

支持情緒記憶的是

被稱為「杏仁核」的 類似杏仁形狀的結構

called the amygdala

及其連接。

and its connections.

Declarative memory, especially the what, where and when of event memory,

陳述性記憶，特別是 關於事件地點與時間的記憶，

is supported by a seahorse-shaped region of the brain

是由腦內一個海馬狀的區域紀錄的，

called the hippocampus.

稱為海馬迴。

The extreme levels of stress experienced during trauma

創傷造成的極端壓力

have very different effects on these two structures.

對這兩個結構的影響不同。

As you can see, as you increase a person's level of stress

如你所見，如果一個人的壓力上升，

from not stressful to slightly stressful,

從沒有壓力到稍微有點壓力，

the hippocampus,

海馬迴支撐事件的記憶，

acting to support the event memory,

increases in its activity

會增加活動量，

and works better to support the storage of that declarative memory.

更好地維護陳述性記憶的儲存。

But as you increase to moderately stressful, intensely stressful

但當壓力持續上升到中、高度壓力，

and then extremely stressful, as would be found in trauma,

或是到了極高壓力時 ——像是遭受創傷後——

the hippocampus effectively shuts down.

海馬迴會自動關閉。

This means that under the high levels of stress hormones

也就是說，是創傷之後

會導致壓力荷爾蒙飆高，

that are experienced during trauma,

we are not storing the details,

不再保存詳盡的細節，

the specific details of what, where and when.

那些關於事件、地點和時間的細節。

Now, while stress is doing that to the hippocampus,

來看看正當壓力影響海馬迴的時候

look at what it does to the amygdala,

會怎麼影響杏仁核，

that structure important for the emotional, non-declarative memory.

發現在那個儲存著情感 和非陳述性記憶的重要部位

Its activity gets stronger and stronger.

活動會越來越強烈。

So what this leaves us with in PTSD

所以 PTSD 會帶給我們過於強烈的情續

is an overly strong emotional -- in this case fear -- memory

——例如恐懼記憶——

that is not tied to a specific time or place,

這些記憶並不關聯到 特定的時間或地點，

because the hippocampus is not storing what, where and when.

這是因為海馬迴不保存 事件的地點和時間。

In this way, these cues can control behavior

如此，這些提示 會在不適當的時刻控制人的行為，

when it's no longer appropriate,

and that's how they become maladaptive.

因而導致適應不良。

So if we know that PTSD is due to maladaptive memories,

如果知道適應不良的記憶會導致 PTSD，

can we use that knowledge to improve treatment outcomes

我們是否可以運用這個知識

來改善 PTSD 患者的治療結果呢？

for patients with PTSD?

A radical new approach being developed to treat post-traumatic stress disorder

用於治療創傷後壓力候群症的 新方案以被開發，

aims to destroy those maladaptive emotional memories

它的目標是消除 適應不良的情緒記憶

that underlie the disorder.

導致的候群症。

This approach has only been considered a possibility

這個方案最近幾年 才被視為一種可能性，

because of the profound changes in our understanding of memory

因為我們對記憶力的理解

出現了極大的改變。

in recent years.

Traditionally, it was thought that making a memory

傳統上，人們認為創造記憶

was like writing in a notebook in pen:

就像是在筆記本裡用鋼筆寫字：

once the ink had dried, you couldn't change the information.

一旦墨水乾透之後， 你無法改變那些訊息。

It was thought that all those structural changes

人們曾經認為

為要提供更多的記憶容量，

that happen in the brain to support the storage of memory

腦內的結構能在六個小時內完成改變，

were finished within about six hours,

and after that, they were permanent.

在那之後，記憶就會變成永久的。

This is known as the consolidation view.

這稱為記憶鞏固概念。

However, more recent research suggests that making a memory

然而最近的研究顯示，

創造記憶比較像 在文字處理程式裡寫字。

is actually more like writing in a word processor.

We initially make the memory and then we save it or store it.

最初我們創造記憶， 然後把它保存。

But under the right conditions, we can edit that memory.

但是在某些情況下， 我們可以編輯那些記憶。

This reconsolidation view suggests that those structural changes

記憶鞏固概念指出，

大腦為了支撐記憶力 而作出的結構改變，

that happen in the brain to support memory

can be undone,

是可以撤消的，

even for old memories.

即使是很舊的記憶。

Now, this editing process isn't happening all the time.

這個記憶的編輯過程不常發生，

It only happens under very specific conditions

只在特定的記憶檢索狀況下才會發生。

of memory retrieval.

So let's consider memory retrieval as being recalling the memory

讓我們將記憶檢索視為調用記憶，

or, like, opening the file.

就像是打開檔案一樣。

Quite often, we are simply retrieving the memory.

通常我們只單純取出記憶，

We're opening the file as read-only.

就像是用「唯讀」模式來打開檔案。

But under the right conditions,

但是，在正確的情況下，

we can open that file in edit mode,

我們可以打開檔案 並設置為編輯模式，

and then we can change the information.

然後我們可以改變裡面的資料。

In theory, we could delete the content of that file,

理論上，我們可以刪除檔案內容，

and when we press save,

當我們按下保存鍵的時候，

that is how the file -- the memory --

那個檔案——也就是記憶——

persists.

就會被存留下來。

Not only does this reconsolidation view

鞏固的概念

不只解釋記憶的奇怪之處

allow us to account for some of the quirks of memory,

like how we all sometimes misremember the past,

——像為什麼有時我們會記錯——

it also gives us a way to destroy those maladaptive fear memories

它還可以讓我們消除

PTSD 適應不良的恐懼記憶。

that underlie PTSD.

All we would need would be two things:

我們只需兩樣：

a way of making the memory unstable -- opening that file in edit mode --

讓記憶變得不穩定的方法 ——用編輯模式打開檔案——

and a way to delete the information.

和刪除資訊的方法。

We've made the most progress

對於如何刪除資訊的研究

with working out how to delete the information.

我們取得了極多的進展。

It was found fairly early on

初期我們發現了一種

that a drug widely prescribed to control blood pressure in humans --

廣泛使用的血壓控制藥物

a beta-blocker called Propranolol --

——稱為普萘洛爾的 β 受體阻滯劑——

could be used to prevent the reconsolidation

可用於防止老鼠的恐懼記憶被鞏固。

of fear memories in rats.

If Propranolol was given while the memory was in edit mode,

在記憶編輯模式使用普萘洛爾後，

rats behaved as if they were no longer afraid of a frightening trigger cue.

老鼠似乎不再害怕 能觸發恐懼的線索。

It was as if they had never learned to be afraid of that cue.

彷彿牠們未曾學過害怕那線索。

And this was with a drug that was safe for use in humans.

人類可以安全使用這個藥物。

Now, not long after that,

不久之後，

it was shown that Propranolol could destroy fear memories in humans as well,

普萘洛爾也被發現可以 消除人類的恐懼記憶，

but critically, it only works if the memory is in edit mode.

但重要的是，記憶要在 編輯模式才會成功。

Now, that study was with healthy human volunteers,

那個研究採用了健康的志願者，

but it's important because it shows that the rat findings

這實驗非常重要，因為它證明了

老鼠的研究結果跟人類相關，

can be extended to humans and ultimately, to human patients.

最終也證實可以醫治病人。

And with humans,

對於人類，

you can test whether destroying the non-declarative emotional memory

你可以測試看看 消除非陳述性情緒記憶

does anything to the declarative event memory.

會不會影響陳述性事件記憶。

And this is really interesting.

這非常有趣。

Even though people who were given Propranolol

即使讓記憶處於編輯模式的人 服用普萘洛爾後

while the memory was in edit mode

were no longer afraid of that frightening trigger cue,

不再害怕激發恐懼的線索，

they could still describe the relationship

他們依然能形容

線索與恐怖結果之間的關聯。

between the cue and the frightening outcome.

It was as if they knew they should be afraid,

就像他們知道自己應該感到害怕，

and yet they weren't.

但卻不害怕。

This suggests that Propranolol can selectively target

這表明了普萘洛爾能針對 非陳述性情緒記憶，

the non-declarative emotional memory

but leave the declarative event memory intact.

同時完好無缺地保留著陳述性記憶。

But critically, Propranolol can only have any effect on the memory

但要緊的是，普萘洛爾 只在編輯模式的情況下對記憶有作用。

if it's in edit mode.

So how do we make a memory unstable?

那麼怎樣把記憶變為不穩定呢？

How do we get it into edit mode?

如何進入編輯模式呢？

Well, my own lab has done quite a lot of work on this.

我的實驗室在這方面做了許多研究。

We know that it depends on introducing some but not too much new information

我們發現這需要依靠 一些不怎麼多的新資訊，

to be incorporated into the memory.

把它併入記憶中。

We know about the different chemicals the brain uses

我們知道大腦會使用不同化學物質

to signal that a memory should be updated

來提醒記憶需要被更新

and the file edited.

並編輯檔案。

Now, our work is mostly in rats,

如今，我們大多數的研究 用在老鼠身上，

but other labs have found the same factors allow memories to be edited in humans,

但是其他實驗室證實了 編輯人類記憶的方法也一樣，

even maladaptive memories like those underlying PTSD.

即使病人有適應不良的記憶， 例如 PTSD。

In fact, a number of labs in several different countries

事實上，在不同國家裡，

have begun small-scale clinical trials of these memory-destroying treatments

數個治療 PTSD 的小型臨床試驗

已經開始了，

for PTSD

and have found really promising results.

並已取得理想的研究結果。

Now, these studies need replication on a larger scale,

這些需要更大規模地重複實驗，

but they show the promise of these memory-destroying treatments

但所有的實驗結果

for PTSD.

都一致顯示可以治療 PTSD。

Maybe trauma memories do not need to be the hell from which we cannot escape.

也許創傷性記憶未必是 我們無法逃脫的地獄。

Now, although this memory-destroying approach holds great promise,

雖然記憶刪除方案充滿希望，

that's not to say that it's straightforward

但是它並不直接了當，

or without controversy.

而且存有爭議。

Is it ethical to destroy memories?

消除記憶是人道的行為嗎？

What about things like eyewitness testimony?

目擊者證詞又如何分辨是非呢？

What if you can't give someone Propranolol

如果有人不能服用普萘洛爾呢？

because it would interfere with other medicines that they're taking?

因為會跟其他藥物相沖 而帶來負面影響。

Well, with respect to ethics and eyewitness testimony,

關於道德和目擊者證詞，

I would say the important point to remember

注重的要點是：

is the finding from that human study.

研究人類所得的結果。

Because Propranolol is only acting on the non-declarative emotional memory,

因為普萘洛爾只會影響 非陳述性情緒記憶，

it seems unlikely that it would affect eyewitness testimony,

看似不會對目擊者證詞起作用，

which is based on declarative memory.

因為那屬於陳述性記憶。

Essentially, what these memory-destroying treatments

本質上，

這些記憶刪除治療方案的目標

are aiming to do

is to reduce the emotional memory,

是「減少」情緒記憶，

not get rid of the trauma memory altogether.

但不是完全消除創傷性事件的記憶。

This should make the responses of those with PTSD

它會讓 PTSD 患者

more like those who have been through trauma

變得更像經歷過創傷的事件，

and not developed PTSD

但沒有患上 PTSD 的人，

than people who have never experienced trauma in the first place.

而不是變成完全沒有 經歷創傷性事件的人。

I think that most people would find that more ethically acceptable

由於這個治療方案 不會創造空虛的記憶。

than a treatment that aimed to create some sort of spotless mind.

這在倫理上比較能讓人接受。

What about Propranolol?

那普萘洛爾呢？

You can't give Propranolol to everyone,

你不能把普萘洛爾開給全部人，

and not everyone wants to take drugs to treat mental health conditions.

而且不是每個人 都想用藥物治療心理健康疾病。

Well, here Tetris could be useful.

這樣的話，俄羅斯方塊會有幫助。

Yes, Tetris.

對的，俄羅斯方塊。

Working with clinical collaborators,

和研究合作者一起工作的時候，

we've been looking at whether behavioral interventions

我們一直在研究

行為干預是否也能夠干涉記憶鞏固。

can also interfere with the reconsolidation of memories.

Now, how would that work?

是怎麼作用的呢？

Well, we know that it's basically impossible

我們都知道，

人基本上不可能同時完成兩個任務，

to do two tasks at the same time

if they both depend on the same brain region for processing.

倘若兩者依賴 相同的大腦區域處理的話。

Think trying to sing along to the radio

就像是一邊跟著收音機唱歌，

while you're trying to compose an email.

一邊寫電郵。

The processing for one interferes with the other.

同時進行這兩個事項會互相干涉。

Well, it's the same when you retrieve a memory,

其實，它就像喚回記憶一樣，

especially in edit mode.

特別是在編輯模式裡。

If we take a highly visual symptom like flashbacks in PTSD

如果我們使用視覺上的徵兆， 比如說 PTSD 的閃回，

and get people to recall the memory in edit mode

讓人們在編輯模式下召回記憶，

and then get them to do a highly engaging visual task

然後讓他們進行 高參與度的視覺活動，

like playing Tetris,

例如玩俄羅斯方塊。

it should be possible to introduce so much interfering information

應該有可能在該存儲中 引入太多的干擾信息，

into that memory

that it essentially becomes meaningless.

實際上使它變得毫無意義。

That's the theory,

這就是當中的理論，

and it's supported by data from healthy human volunteers.

從健康人類志願者得來的 研究數據支持了這個理論。

Now, our volunteers watched highly unpleasant films --

我們的志願者觀看 非常不愉快的電影——

so, think eye surgery, road traffic safety adverts,

例如眼睛手術、 道路交通安全的廣告、

Scorsese's "The Big Shave."

史柯西斯的《剃鬚記》。

These trauma films produce something like flashbacks

健康志願者觀看它們一周後，

in healthy volunteers for about a week after viewing them.

這些創傷性的電影 導致了閃回的反應。

We found that getting people to recall those memories,

我們發現

如果一邊讓他們回想這些記憶，

the worst moments of those unpleasant films,

這些電影裡最糟糕的畫面，

and playing Tetris at the same time,

然後一邊玩俄羅斯方塊的話，

massively reduced the frequency of the flashbacks.

出現閃回的次數大規模地下降。

And again: the memory had to be in edit mode for that to work.

再說一遍：記憶必須是 在編輯模式下才會成功。

Now, my collaborators have since taken this to clinical populations.

我的合作者把這實驗帶到臨床患者。

They've tested this in survivors of road traffic accidents

他們給交通意外生還者

and mothers who've had emergency Caesarean sections,

和做過緊急剖腹手術的母親 進行了這個實驗，

both types of trauma that frequently lead to PTSD,

這兩種創傷性事件經常導致 PTSD。

and they found really promising reductions in symptoms

在這兩樣臨床實驗裡

in both of those clinical cases.

發現症狀減少了。

So although there is still much to learn and procedures to optimize,

雖然我們仍需更深入了解和優化程序，

these memory-destroying treatments hold great promise

但這些刪除記憶的治療方案 對於治療心理健康疾病

for the treatment of mental health disorders

like PTSD.

——例如 PTSD——可能大大有效。

Maybe trauma memories do not need to be a hell from which we cannot escape.

也許創傷性記憶 並不是無法脫離的地獄。

I believe that this approach

我相信這方式能讓人選擇

should allow those who want to

to turn the page on chapters of their lives

跨過這些他們希望 未曾有過的生命章節，

that they would prefer to never have experienced,

and so improve our mental health.

改善心理健康。

Thank you.

謝謝。

(Applause)

（掌聲）