You can grow new brain cells. Here's how | Sandrine Thuret | TED

譯者: Wink Wong 審譯者: Seke Wei

Can we, as adults, grow new nerve cells?

我們成人可否長出新的神經細胞？

There's still some confusion about that question,

有些人對這個問題感到疑惑，

as this is a fairly new field of research.

畢竟這是較新的研究領域。

For example, I was talking to one of my colleagues, Robert,

例如我曾經跟同事Robert聊過，

who is an oncologist,

他是腫瘤專家，

and he was telling me,

他對我説，

"Sandrine, this is puzzling.

Sandrine，我真是不明白

Some of my patients that have been told they are cured of their cancer

我明明跟病人講， 他們的癌症已經痊癒，

still develop symptoms of depression."

他們卻出現了抑鬱症。

And I responded to him,

我回答說，

"Well, from my point of view that makes sense.

對我而言，這容易理解。

The drug you give to your patients that stops the cancer cells multiplying

因為你給病人開的藥 阻止了癌細胞繁殖，

also stops the newborn neurons being generated in their brain."

也同時阻礙了他們的腦部 生長新的神經細胞。

And then Robert looked at me like I was crazy and said,

接著Robert望向我， 好像我神經錯亂，他説，

"But Sandrine, these are adult patients --

可是Sandrine， 這些患者都是成年人，

adults do not grow new nerve cells."

成年人是不會長新神經細胞的。

And much to his surprise, I said, "Well actually, we do."

出乎他意料之外， 我說，其實可以的。

And this is a phenomenon that we call neurogenesis.

我們稱這種現象是神經再生。

[Neurogenesis]

［神經再生］

Now Robert is not a neuroscientist,

因為Robert不是神經學家

and when he went to medical school he was not taught what we know now --

以前他讀醫學院時，並沒有 學過我們今天認識的現象，

that the adult brain can generate new nerve cells.

成人腦部是可以生長新神經細胞的。

So Robert, you know, being the good doctor that he is,

Robert是一位好醫生，

wanted to come to my lab

他要來我的實驗室，

to understand the topic a little bit better.

想多了解這個議題。

And I took him for a tour

於是我向他介紹

of one of the most exciting parts of the brain

腦部最令人興奮之處，

when it comes to neurogenesis --

就是它有神經再生能力--

and this is the hippocampus.

這是海馬體

So this is this gray structure in the center of the brain.

這是灰質，位於腦部的中央。

And what we've known already for very long,

我們很早已經知道

is that this is important for learning, memory, mood and emotion.

這些部分對於學習、記憶、 心情、和情感尤其重要。

However, what we have learned more recently

但是直到最近我們才知曉

is that this is one of the unique structures of the adult brain

這是成人腦部之中 一個特別的組織

where new neurons can be generated.

可以產生新的神經細胞。

And if we slice through the hippocampus

如果我們切開海馬體

and zoom in,

然後用鏡頭放大看裡面的東西，

what you actually see here in blue

便可以見到這個藍色的地方

is a newborn neuron in an adult mouse brain.

它是成年老鼠腦部的新生神經。

So when it comes to the human brain --

說到人類的腦部--

my colleague Jonas Frisén from the Karolinska Institutet,

我的同事Jonas Frisen 來自 Karolinska研究所，

has estimated that we produce 700 new neurons per day

據其估計，我們的海馬體

in the hippocampus.

每天有700個新生的神經。

You might think this is not much,

你可能會覺得跟人體內

compared to the billions of neurons we have.

數十億的神經相比， 這實在是微不足道。

But by the time we turn 50,

可是，在我們到達50歲前，

we will have all exchanged the neurons we were born with in that structure

海馬體內的天生神經

with adult-born neurons.

將會因此全由成年再生的 神經替換掉。

So why are these new neurons important and what are their functions?

為什麼這些新神經那麼重要，其功能為何？

First, we know that they're important for learning and memory.

首先，我們知道這些神經 對學習和記憶很重要。

And in the lab we have shown

我們做了實驗證明

that if we block the ability of the adult brain

如果我們阻止成年腦部

to produce new neurons in the hippocampus,

在海馬體製造新神經，

then we block certain memory abilities.

則同時我們也阻礙了 某些記憶能力的發展。

And this is especially new and true for spatial recognition --

特別是有關空間認知的最新發現更是如此，

so like, how you navigate your way in the city.

這說明你為何可以在城裏認路。

We are still learning a lot,

我們不停地學習，

and neurons are not only important for memory capacity,

神經不單影響記憶容量，

but also for the quality of the memory.

也影響記憶品質。

And they will have been helpful to add time to our memory

這些細胞將會延長我們的記憶，

and they will help differentiate very similar memories, like:

也會協助我們從類似記憶中， 分辨出細微的差異：

how do you find your bike

例如你每天出入同一個車站，

that you park at the station every day in the same area,

腳踏車停在同一塊區域， 你怎麼找得到

but in a slightly different position?

自己今天停放的不同位置？

And more interesting to my colleague Robert

我的同事Robert一直對我們進行的

is the research we have been doing on neurogenesis and depression.

神經再生和抑鬱症研究感興趣。

So in an animal model of depression,

在抑鬱症的動物模型中，

we have seen that we have a lower level of neurogenesis.

我們見到動物的神經再生量較低。

And if we give antidepressants,

但是如果我們給予抗抑鬱藥，

then we increase the production of these newborn neurons,

便會增加其新生神經的數量，

and we decrease the symptoms of depression,

並減少抑鬱症狀。

establishing a clear link between neurogenesis and depression.

這證明神經再生跟抑鬱症 有明顯的關係。

But moreover, if you just block neurogenesis,

還有，若你阻止神經再生，

then you block the efficacy of the antidepressant.

則你也阻止抗抑鬱藥發揮效用。

So by then, Robert had understood

因此，Robert開始明白，

that very likely his patients were suffering from depression

他的患者為何癌症已經痊癒，

even after being cured of their cancer,

卻常受抑鬱症之苦的理由，

because the cancer drug had stopped newborn neurons from being generated.

因為癌症藥阻止了 新神經的生長。

And it will take time to generate new neurons

而新神經需要時間生長，

that reach normal functions.

才能達到正常功能。

So, collectively, now we think we have enough evidence

所以，我們現在共同認識到， 已經有足夠的證據顯示

to say that neurogenesis is a target of choice

神經再生是重要關鍵，

if we want to improve memory formation or mood,

如果我們想要改善記憶或情緒

or even prevent the decline associated with aging,

或者預防因為老化或壓力

or associated with stress.

招致的腦部衰退。

So the next question is:

所以，接下來要問的問題是：

can we control neurogenesis?

我們可以控制神經再生嗎？

The answer is yes.

答案是可以的。

And we are now going to do a little quiz.

現在就讓大家來做一個小測驗。

I'm going to give you a set of behaviors and activities,

我將提示一連串的行為和活動，

and you tell me if you think they will increase neurogenesis

請大家告訴我， 它們會助長神經再生

or if they will decrease neurogenesis.

或者減少神經再生。

Are we ready?

預備好了嗎？

OK, let's go.

好，開始。

So what about learning?

你認為學習怎樣呢？

Increasing?

增加？

Yes.

對。

Learning will increase the production of these new neurons.

學習會幫助腦部製造 更多新神經。

How about stress?

壓力又如何？

Yes, stress will decrease the production of new neurons in the hippocampus.

對，壓力會減低海馬體 的神經再生。

How about sleep deprivation?

睡眠不足又如何？

Indeed, it will decrease neurogenesis.

其實那會減低神經再生。

How about sex?

性行為又如何？

Oh, wow!

噢，哇！

(Laughter)

（笑聲）

Yes, you are right, it will increase the production of new neurons.

對，你們答對了。 那會增加新神經生長。

However, it's all about balance here.

但是每樣事都要適可而止。

We don't want to fall in a situation --

我們不希望陷入另一種情況--

(Laughter)

（笑聲）

about too much sex leading to sleep deprivation.

太多性行為會導致睡眠不足。

(Laughter)

（笑聲）

How about getting older?

年老又怎樣？

So the neurogenesis rate will decrease as we get older,

隨著年紀漸長，神經再生 的速度會慢下來，

but it is still occurring.

但仍然會發生。

And then finally, how about running?

最後，跑步又如何？

I will let you judge that one by yourself.

我讓大家自己來判斷。

So this is one of the first studies

這是我們最早作的一個硏究，

that was carried out by one of my mentors, Rusty Gage from the Salk Institute,

是由我的導師 Rusty Gage 做實驗。 他來自 Salk 研究所。

showing that the environment can have an impact

這個實驗證明環境會影響

on the production of new neurons.

新神經的生長。

And here you see a section of the hippocampus of a mouse

這是一隻老鼠的海馬體切片，

that had no running wheel in its cage.

牠的籠子沒有轉輪。

And the little black dots you see are actually newborn neurons-to-be.

而那些黑點其實是 新生的準神經。

And now, you see a section of the hippocampus of a mouse

現在你看看另一隻老鼠的海馬體切片，

that had a running wheel in its cage.

牠的籠子裝了轉輪。

So you see the massive increase

你可以看到切片上有大量

of the black dots representing the new neurons-to-be.

新増的黑點，那是新生 的準神經。

So activity impacts neurogenesis, but that's not all.

所以活動會影響神經再生， 但是不只這樣。

What you eat will have an effect

你吃什麼也會影響

on the production of new neurons in the hippocampus.

海馬體的神經再生。

So here we have a sample of diet --

這裡有份飲食樣本

of nutrients that have been shown to have efficacy.

內含一些有效的營養物。

And I'm just going to point a few out to you:

我現在只提出幾點供參考：

Calorie restriction of 20 to 30 percent will increase neurogenesis.

減少20-30％的卡路里攝取量 會增加神經再生。

Intermittent fasting -- spacing the time between your meals --

間歇性的禁食，把兩餐之間 的用餐時間隔開一點，

will increase neurogenesis.

有助神經再生。

Intake of flavonoids,

攝食類黃酮，

which are contained in dark chocolate or blueberries,

黑巧克力或者藍莓都含有類黃酮，

will increase neurogenesis.

有助增加神經再生。

Omega-3 fatty acids,

奧米加-3 脂肪酸

present in fatty fish, like salmon,

可以在多脂魚類，例如鮭魚中找到，

will increase the production of these new neurons.

會增加神經再生。

Conversely, a diet rich in high saturated fat

相反的，常吃太多飽和脂肪食物

will have a negative impact on neurogenesis.

會對神經再生有壞影響。

Ethanol -- intake of alcohol -- will decrease neurogenesis.

乙醇，即喝酒，會減低 神經再生。

However, not everything is lost;

但不是每樣都要捨棄；

resveratrol, which is contained in red wine,

紅酒含有白藜蘆醇(resveratrol)

has been shown to promote the survival of these new neurons.

已經證明可以增加 新神經的存活率。

So next time you are at a dinner party,

所以下次你參加晚宴，

you might want to reach for this possibly "neurogenesis-neutral" drink.

也許可以去拿這杯 可能《不影響神經再生》的飲品。

(Laughter)

（笑聲）

And then finally, let me point out the last one --

最後，我想提出最後一點，

a quirky one.

較古怪的一點。

So Japanese groups are fascinated with food textures,

有日本團隊著迷於食物軟硬質地的研究，

and they have shown that actually soft diet impairs neurogenesis,

其結果顯示太軟的飲食， 有礙神經再生，

as opposed to food that requires mastication -- chewing -- or crunchy food.

這跟需要咀嚼或者鬆脆的食物 有助再生剛好相反。

So all of this data,

有關上述數據，

where we need to look at the cellular level,

我們皆需從細胞層次觀察，

has been generated using animal models.

其資料皆來自動物模型。

But this diet has also been given to human participants,

但這些飲食我們也有 給人做實驗。

and what we could see is that the diet modulates memory and mood

我們觀察到這些飲食 調控記憶和情緒好壞的情形，

in the same direction as it modulates neurogenesis,

跟調控神經再生多寡的方向一致，

such as: calorie restriction will improve memory capacity,

例如限制卡路里攝取 會改善記憶容量，

whereas a high-fat diet will exacerbate symptoms of depression --

而高脂肪飲食會加劇抑鬱症狀，

as opposed to omega-3 fatty acids, which increase neurogenesis,

相反的，奥米加-3 脂肪酸 有助神經再生，

and also help to decrease the symptoms of depression.

也有助減輕抑鬱症狀。

So we think that the effect of diet

所以我們認為飲食會影響

on mental health, on memory and mood,

精神健康，記憶和情緒，

is actually mediated by the production of the new neurons in the hippocampus.

其實是藉由調控海馬體內 新神經的生長而達成的。

And it's not only what you eat,

影響因子並不只是你吃下什麼東西，

but it's also the texture of the food, when you eat it

還包括食物的軟硬質地，何時進食，

and how much of it you eat.

及吃了多少份量。

On our side -- neuroscientists interested in neurogenesis --

就研究神經再生的神經科學家而言，

we need to understand better the function of these new neurons,

我們需要再深入了解 這些新神經的功用，

and how we can control their survival and their production.

怎樣才能控制其存活及再生率。

We also need to find a way to protect the neurogenesis of Robert's patients.

我們也需想辦法保護 Robert患者的神經再生。

And on your side --

而就你們而言---

I leave you in charge of your neurogenesis.

就請大家好好負責自己的神經再生吧。

Thank you.

謝謝。

(Applause)

（鼓掌聲）

Margaret Heffernan: Fantastic research, Sandrine.

Margaret Heffernan：Sandrine， 你的研究非常好。

Now, I told you you changed my life --

我現在告訴你， 你改變了我的生活。

I now eat a lot of blueberries.

我現在吃很多藍莓。

Sandrine Thuret: Very good.

Sandrine Thuret：很好。

MH: I'm really interested in the running thing.

MH： 我對跑步之類很有興趣。

Do I have to run?

我是否一定要跑步？

Or is it really just about aerobic exercise,

或者也可作些有氧運動，

getting oxygen to the brain?

讓腦部吸入氧氣？

Could it be any kind of vigorous exercise?

做其他劇烈運動也可以嗎？

ST: So for the moment,

ST：目前來看，

we can't really say if it's just the running itself,

我們真的不會說只有跑步才有用，

but we think that anything that indeed will increase the production --

但會認為只要可以幫助細胞再生--

or moving the blood flow to the brain,

或是讓血液流向腦部的運動，

should be beneficial.

都是有益的。

MH: So I don't have to get a running wheel in my office?

MH：那麼我不用在辦公室 安裝一個轉輪嗎？

ST: No, you don't!

ST：不用了。

MH: Oh, what a relief! That's wonderful.

MH： 噢，鬆了一口氣！ 真好。

Sandrine Thuret, thank you so much.

多謝你，Sandrine Thuret

ST: Thank you, Margaret.

ST：多謝，Margaret。

(Applause)

(鼓掌聲）