What hallucination reveals about our minds | Oliver Sacks

オリバー・サックス： 幻覚が解き明かす人間のマインド

翻訳: Takako Sato 校正: Yasushi Aoki

We see with the eyes,

人は目だけではなく

but we see with the brain as well.

脳でも見ています

And seeing with the brain is often called imagination.

想像は脳で見るものです

想像が描き出す心象は馴染みがあるでしょう

And we are familiar with the landscapes of our own imagination,

our inscapes.

どんな人だって想像はしますから

We've lived with them all our lives.

But there are also hallucinations as well.

しかし 幻覚もあります

And hallucinations are completely different.

幻覚は全く異なるもので

They don't seem to be of our creation.

我々の創造ではありません

They don't seem to be under control.

抑制もできません

They seem to come from the outside and to mimic perception.

幻覚は外から現れて

現実と区別がつきにくい

So I am going to be talking about hallucinations

その幻覚について話をします

and a particular sort of visual hallucination,

私の患者が体験した－

which I see among my patients.

特殊な幻視を紹介します

A few months ago, I got a phone call from a nursing home where I work.

数か月前に電話がありました

私が働く老人ホームからです

They told me that one of their residents, an old lady in her 90s,

入居中の90代の女性が

was seeing things,

幻覚を見ているので

and they wondered if she'd gone bonkers

気が狂ったのではないか と

or, because she was an old lady,

または 高齢のために

whether she'd had a stroke, or whether she had Alzheimer's.

脳卒中かアルツハイマーではないか と

And so they asked me if I would come and see Rosalie,

それで診に来てほしいと頼まれました

the old lady.

ロザリーおばあさんです

I went in to see her.

診に行ったら

It was evident straightaway that she was perfectly sane

彼女が正気なのは

明らかでした

and lucid and of good intelligence,

頭ははっきりしていて 理解力もある

but she'd been very startled and very bewildered,

でも非常に当惑していました

because she'd been seeing things.

幻覚が現れるからです

And she told me -- the nurses hadn't mentioned this --

事前に聞いていませんでしたが

彼女は盲目だったのです

that she was blind,

彼女は5年前に

that she had been completely blind from macular degeneration for five years.

加齢黄斑変性症のため 失明したのですが

But now, for the last few days, she'd been seeing things.

数日前から幻覚を見るようになりました

So I said, "What sort of things?"

“何が見える？” と聞くと

And she said, "People in Eastern dress,

“東洋風の服を着た人たちが

in drapes, walking up and down stairs.

階段を上り下りしている

A man who turns towards me and smiles,

私の方を見て微笑んでいる男

but he has huge teeth on one side of his mouth.

口の脇から大きな歯が出ているの

Animals too.

動物も見える

I see a white building. It's snowing, a soft snow.

白い建物　 わた雪が降っている

I see this horse with a harness, dragging the snow away.

雪かき用ハーネスをつけた馬が見える

Then, one night, the scene changes.

そして ある晩 シーンが変わったの

I see cats and dogs walking towards me.

猫や犬が寄ってきて

They come to a certain point and then stop.

ある程度近づいたら立ち止まる

Then it changes again.

そして また変わる

I see a lot of children. They're walking up and down stairs.

階段を上り下りしている たくさんの子ども

They wear bright colors, rose and blue,

バラ色や青の明るい服を着ている

like Eastern dress."

東洋の服のよう”

Sometimes, she said, before the people come on,

その人たちが現れる前に

she may hallucinate pink and blue squares on the floor,

床に広がるピンクと青の四角い模様が

which seem to go up to the ceiling.

天井に上がる幻覚が見えることも

I said, "Is this like a dream?"

“夢のような感じ？” と尋ねると

And she said, "No, it's not like a dream. It's like a movie."

“いいえ 　夢ではなく映画のよう

色もついていて 動きがある

She said, "It's got color. It's got motion.

But it's completely silent, like a silent movie."

でも無声映画のように音がない”

And she said it's a rather boring movie.

やや退屈な映画だ と

(Laughter)

“東洋風の服をまとった人たちは

She said, "All these people with Eastern dress,

walking up and down, very repetitive, very limited."

上り下りを繰り返すばかりで 行動が限られている”

(Laughter)

（笑）

And she had a sense of humor.

ユーモアのある女性なんです

She knew it was a hallucination, but she was frightened.

幻覚だとわかっていても

怖がっていた　95年の人生で

She had lived 95 years,

and she'd never had a hallucination before.

幻覚を見たことがなかったから

She said that the hallucinations were unrelated to anything she was thinking

その幻覚は彼女の思考や感覚

行動と無関係だというのに

or feeling or doing,

やって来ては消えていくようです

that they seemed to come on by themselves, or disappear.

She had no control over them.

コントロールすることはできず

彼女には幻覚の中の

She said she didn't recognize any of the people or places

人物や場所は

in the hallucinations,

どれも見覚えがない

and none of the people or the animals --

しかも人も動物も

well, they all seemed oblivious of her.

彼女に気がついていないようだった

And she didn't know what was going on.

彼女は状況が把握できず

She wondered if she was going mad or losing her mind.

狂ってしまったかと

心配していました

Well, I examined her carefully.

私は入念に診察しました

She was a bright old lady,

陽気なおばあさんで

異常はなし　体調良好

perfectly sane.

She had no medical problems.

She wasn't on any medications which could produce hallucinations.

幻覚を引き起こす薬も飲んでいません

But she was blind.

盲目ということだけ

And I then said to her, "I think I know what you have."

それで 言ったんです

“察しがつきました

I said, "There is a special form of visual hallucination

視力低下や失明によって起きる－

which may go with deteriorating vision or blindness.

特殊な幻視があるんです”

This was originally described," I said,

“これはシャルル ボネという男性が

"right back in the 18th century,

18世紀に初めて

by a man called Charles Bonnet.

記述した症状です

And you have Charles Bonnet syndrome.

あなたはシャルルボネ症候群です

There's nothing wrong with your brain. There's nothing wrong with your mind.

脳も精神も正常

シャルルボネ症候群ですよ”

You have Charles Bonnet syndrome."

And she was very relieved at this,

それを聞いて彼女は安心し

that there was nothing seriously the matter,

深刻な問題ではないことにホッとした

and also rather curious.

そして むしろ 好奇の目で

She said, "Who is this Charles Bonnet?"

“シャルルボネって誰？

She said, "Did he have them himself?"

彼にも幻覚が見えたの？” と

And she said, "Tell all the nurses that I have Charles Bonnet syndrome."

さらには “看護師のみんなに

私はシャルルボネ症候群だと言ってちょうだい”

(Laughter)

（笑）

"I'm not crazy. I'm not demented. I have Charles Bonnet syndrome."

“狂ってもボケてもいない 　シャルルボネ症候群なだけ”

Well, so, I did tell the nurses.

彼女の言うとおりにしました

Now this, for me, is a common situation.

これは よくあるケースです

I work in old-age homes, largely.

主として老人ホームで仕事をするので

I see a lot of elderly people

高齢者が相手です

聴覚 視覚障害者も多く

who are hearing-impaired or visually impaired.

About 10 percent of the hearing-impaired people

聴覚障害者の約１割は

get musical hallucinations.

音楽性幻聴が聴こえます

And about 10 percent of the visually impaired people

視覚障害者の約１割は

get visual hallucinations.

幻視を見ます

You don't have to be completely blind,

全盲ではなく

only sufficiently impaired.

弱視も含まれます

Now, with the original description in the 18th century,

18世紀に話を移しますが

Charles Bonnet did not have them.

この幻覚症状があったのは

His grandfather had these hallucinations.

シャルルボネではなく彼の祖父でした

His grandfather was a magistrate, an elderly man.

祖父は高齢の裁判官でした

He'd had cataract surgery.

白内障の手術を受け

His vision was pretty poor.

視力は相当悪かった

And in 1759, he described to his grandson

1759年 彼は自分の幻覚症状を

various things he was seeing.

孫に話したのです

The first thing he said was he saw a handkerchief in midair.

まず彼が話したのは

宙に浮くハンカチです

It was a large blue handkerchief with four orange circles.

大判で青地に

オレンジの丸が4つ

And he knew it was a hallucination.

祖父は幻覚だと認識していました

You don't have handkerchiefs in midair.

宙に浮くハンカチはありませんから

And then he saw a big wheel in midair.

そして宙に浮く大きな車輪を見た

But sometimes he wasn't sure whether he was hallucinating or not,

でも 時々 幻覚か否か自信がなかった

because the hallucinations would fit in the context of the visions.

幻覚が身の回りのものと

調和しているからです

So on one occasion, when his granddaughters were visiting them,

ある日 孫娘が来ていた時

“男前の若い衆は誰かね？” と聞きました

he said, "And who are these handsome young men with you?"

(Laughter)

And they said, "Alas, Grandpapa, there are no handsome young men."

“まぁ お祖父様　そんな人いないわ”

And then the handsome young men disappeared.

そうすると その男たちは姿を消しました

It's typical of these hallucinations

幻覚ではよくあることです

that they may come in a flash and disappear in a flash.

パッと現れ パッと消える

They don't usually fade in and out.

徐々に現れたり消えたりしません

They are rather sudden, and they change suddenly.

むしろ突然起きるのです

シャルルボネの祖父には

Charles Lullin, the grandfather,

saw hundreds of different figures,

何百もの人影や形

different landscapes of all sorts.

風景が見えました

On one occasion, he saw a man in a bathrobe smoking a pipe,

バスローブ姿でパイプを吸う男も見えました

and realized it was himself.

それは彼自身だったのです

That was the only figure he recognized.

見覚えのあるのは それだけでした

On one occasion, when he was walking in the streets of Paris,

ある時 パリの街を歩いていたら

he saw -- this was real -- a scaffolding.

目に入った本物の工事現場の足場が

But when he got back home, he saw a miniature of the scaffolding,

帰宅すると15cmのミニチュアとなって

six inches high,

書斎の机にのっていました

on his study table.

This repetition of perception is sometimes called "palinopsia."

映像を繰返し見ることは

反復視と呼ばれます

シャルルボネの祖父やロザリーに

With him and with Rosalie,

what seems to be going on --

起こっている現象を

and Rosalie said, "What's going on?" --

ロザリーに説明しました

and I said that as you lose vision,

視力を失うと 脳の視覚部分に

as the visual parts of the brain are no longer getting any input,

入る情報が無くなるため

they become hyperactive and excitable,

そこが活動過多になります

and they start to fire spontaneously.

そして自発的に作用してしまい

幻覚を見始めるのです

And you start to see things.

The things you see can be very complicated indeed.

時に内容も非常に複雑化します

別の患者の体験です

With another patient of mine who also had some vision,

その女性は弱視で

彼女に見えるものは厄介でした

the visions she had could be disturbing.

On one occasion, she said she saw a man in a striped shirt in a restaurant.

ある時 彼女はレストランで

縞模様のシャツを着た男を見た

And he turned round,

男は彼女の方を振り向き

and then he divided into six figures in striped shirts,

6人に分離して 彼女の方へと

who started walking towards her.

歩き始めたのです

And then the six figures came together, like a concertina.

そして 6人はスーっと1人に戻りました

Once, when she was driving,

ある時 彼女は夫が運転する－

or rather, her husband was driving,

車に乗っていたら

the road divided into four

道が4つに分かれました

and she felt herself going simultaneously up four roads.

そして彼女も4つに分かれて進む感覚を覚えました

動きのある幻覚も見えました

She had very mobile hallucinations as well.

A lot of them had to do with a car.

その多くは車に関連したものでした

Sometimes she would see a teenage boy sitting on the hood of the car.

時々彼女はボンネットに座っている―

10代の男の子が見えました

He was very tenacious,

車にくっつき 道を曲がるたびに

and he moved rather gracefully when the car turned.

優雅に動くのです

And then when they came to a stop,

そして 車が止まると 男の子は

the boy would do a sudden vertical takeoff, 100 foot in the air,

30m 真上に急上昇して

and then disappear.

姿を消してしまうのです

Another patient of mine had a different sort of hallucination.

こんな幻覚を見る患者もいました

This was a woman who didn't have trouble with her eyes

その女性は目には問題ないけれど

but the visual parts of her brain,

脳の視覚部分に問題がありました

a little tumor in the occipital cortex.

後頭皮質にある小さな腫瘍です

And, above all, she would see cartoons.

とりわけ 彼女にはアニメ映像が見えました

And these cartoons would be transparent,

そのアニメは透けて見えるもので

and would cover half the visual field, like a screen.

画面のように視野の半分を占めています

And especially, she saw cartoons of Kermit the Frog.

よく見るのはカエルのカーミットでした

(Laughter)

（笑）

Now, I don't watch Sesame Street,

私はセサミストリートは見ませんが

彼女は こう主張するんです

but she made a point of saying,

"Why Kermit?" she said, "Kermit the Frog means nothing to me."

“なぜ？カーミットが出てくる理由がわからない

You know, I was wondering about Freudian determinants: Why Kermit?

フロイト的な意味が知りたい

なぜカーミットなの？

"Kermit the Frog means nothing to me."

何の意味もなさないのに”

She didn't mind the cartoons too much.

アニメは我慢できても

But what did disturb her

しつこく出てくるイメージや顔の幻覚に

was she got very persistent images or hallucinations of faces,

彼女もロザリーも困っていました

and as with Rosalie, the faces were often deformed,

多くの場合　巨大な歯や目をした

with very large teeth or very large eyes.

デフォルメされた顔が見えるからです

And these frightened her.

彼女は怖がっていました

Well, what is going on with these people?

彼らには何が起きていたのでしょう

As a physician, I have to try and define what's going on

医者である私は患者の症状を見極め

and to reassure people,

安心させるのが仕事です

especially to reassure them that they're not going insane.

狂ったのではないと伝えるのは特にそうです

先ほども言いましたが 視覚障害者の

Something like 10 percent, as I said,

of visually impaired people get these.

1割がこの症状を持っています

But no more than one percent of the people acknowledge them,

しかし 症状を訴えるのは そのうちの1％以下

because they are afraid they will be seen as insane or something.

精神障害だと思われるのが怖いからです

And if they do mention them to their own doctors,

病院に行っても誤診される－

可能性だってあります

they may be misdiagnosed.

In particular, the notion is that if you see things or hear things,

特に 幻覚の概念は

気が狂ってる とみられがちです

you're going mad.

But the psychotic hallucinations are quite different.

しかし 精神病性幻覚は かなり違います

Psychotic hallucinations, whether they are visual or vocal,

精神病性の幻視や幻聴の場合

they address you.

声をかけてくる　責められる

They accuse you, they seduce you, they humiliate you, they jeer at you.

誘惑してくる　侮辱される

馬鹿にされる

You interact with them.

巻き込まれてしまいます

There is none of this quality of being addressed

シャルルボネ症候群において

with these Charles Bonnet hallucinations.

声をかけられることはありません

There is a film. You're seeing a film which has nothing to do with you --

自分とは無関係の映画を見るようなもの

or that's how people think about it.

そのように 捉えられています

There is also a rare thing called temporal lobe epilepsy,

側頭葉てんかん という稀なケースがあります

and sometimes, if one has this,

この症状は 過去に遡る感覚や

one may feel oneself transported back to a time and place in the past.

以前訪れた場所へ戻るような

感覚が生じることがあります

You're at a particular road junction.

ある交差点に立っている

You smell chestnuts roasting.

焼き栗の香りがする

You hear the traffic. All the senses are involved.

車の音　五感で感じ取れます

彼女を待っていた－

And you're waiting for your girl.

And it's that Tuesday evening back in 1982.

忘れもしない1982年 あの火曜の夜

The temporal lobe hallucinations are all sense hallucinations,

側頭葉に関わる幻覚は

すべての感覚に関係しています

full of feeling, full of familiarity,

感覚があり 馴染みがあり

located in space and time,

場所や時間もはっきりしていて

coherent, dramatic.

話に筋が通っていて芝居のよう

The Charles Bonnet ones are quite different.

シャルルボネは かなり違います

In the Charles Bonnet hallucinations, you have all sorts of levels,

シャルルボネ症候群には

様々なレベルがあります

from the geometrical hallucinations --

幾何学模様の幻覚や

the pink and blue squares the woman had --

ロザリーが見たピンクや青の四角

up to quite elaborate hallucinations

人や 特に顔の出てくる

with figures and especially faces.

とても精緻な幻覚もあります

Faces, and sometimes deformed faces,

デフォルメされた顔が現れるのは

are the single commonest thing in these hallucinations.

シャルルボネ症候群で

最も一般的です

And one of the second commonest is cartoons.

2つ目によくあるのはアニメ

So, what is going on?

これは どういうことか

Fascinatingly, in the last few years,

面白いことに過去数年の間に

it's been possible to do functional brain imagery,

幻覚症状の最中にfMRIを使用して

to do fMRI on people as they are hallucinating,

脳機能の画像化が可能になりました

実際に幻覚が現れているときに

and, in fact, to find that different parts of the visual brain are activated

異なる脳の視覚部分が

as they are hallucinating.

活発化することが特定されました

When people have these simple, geometrical hallucinations,

単純な幾何学模様が現れるときは

the primary visual cortex is activated.

一次視覚野が活発化します

This is the part of the brain which perceives edges and patterns.

脳は この領域でへりや模様を知覚します

You don't form images with your primary visual cortex.

一次視覚野で画像を作りだすのではありません

When images are formed,

画像が作りだされるとき

a higher part of the visual cortex is involved, in the temporal lobe.

高次の視覚野が

側頭葉と作用します

特に 側頭葉の一部は

And in particular, one area of the temporal lobe

is called the fusiform gyrus.

紡錘状回と呼ばれています

And it's known that if people have damage in the fusiform gyrus,

紡錘状回がダメージを受けると

they may lose the ability to recognize faces.

顔を認識できなくなることがあります

But if there's an abnormal activity in the fusiform gyrus,

しかし紡錘状回が異常に働くと

they may hallucinate faces,

顔の幻覚を見ることがあります

and this is exactly what you find in some of these people.

これが 患者に起きていることだったのです

There is an area in the anterior part of this gyrus

この脳回の前方には

where teeth and eyes are represented,

歯と目を思い描く領域があります

and that part of the gyrus is activated

巨大な歯と目の幻覚が見えるときは

when people get the deformed hallucinations.

脳回のその部分が活発化しています

There is another part of the brain which is especially activated

脳の別の部分は

アニメが見えるときに

when one sees cartoons.

活発になります

It's activated when one recognizes cartoons,

アニメを見たり描いたり

when one draws cartoons and when one hallucinates them.

アニメの幻覚発生時に活動しています

It's very interesting that that should be specific.

特異性があって興味深いんです

There are other parts of the brain which are specifically involved

脳の他の部分では具体的に

with the recognition and hallucination of buildings and landscapes.

建物 風景の認識や幻覚に

関連する部分があります

Around 1970, it was found that there were not only parts of the brain,

1970年頃 脳の決まった部分のみならず

but particular cells.

特定の細胞があることがわかりました

"Face cells" were discovered around 1970.

1970年頃 顔細胞が発見されました

And now we know that there are hundreds of other sorts of cells,

今では何百種類もの

細胞が発見されています

which can be very, very specific.

非常に特有な細胞です

So you may not only have "car" cells, you may have "Aston Martin" cells.

ですから もしかしたら

車細胞だけではなく

アストンマーチン細胞があるかも

(Laughter)

（笑）

I saw an Aston Martin this morning. I had to bring it in.

今朝アストンマーチンを見たので

話したかったんだ

(Laughter)

既に どこかにあるはずだよ

And now it's in there, somewhere.

So --

（笑）

(Laughter)

now, at this level, in what's called the inferotemporal cortex,

下側頭葉皮質と呼ばれる このレベルでは

視覚画像や断片しか

there are only visual images,

or figments or fragments.

処理されません

It's only at higher levels that the other senses join in

他の感覚が加わってくるのは

もっと高次の領域です

and there are connections with memory and emotion.

そして記憶や感情と関連しています

シャルルボネ症候群では

And in the Charles Bonnet syndrome,

you don't go to those higher levels.

このレベルまでは達しません

You're in these levels of inferior visual cortex,

下側頭葉皮質において

where you have thousands and tens of thousands

何千も 何百万もの

and millions of images,

イメージや断片的な作り事が

or figments or fragmentary figments,

決まった細胞や

all neurally encoded in particular cells or small clusters of cells.

細胞の小さな固まりに

神経符号化される部分で生じます

Normally, these are all part of the integrated stream of perception,

通常 これはどれも知覚や想像の

一体化した流れの一部なのです

or imagination,

and one is not conscious of them.

人間は意識していません

It is only if one is visually impaired or blind

視覚障害者である場合に限り

that the process is interrupted.

この過程が中断されます

And instead of getting normal perception,

そして 正常な知覚を得る代わりに

you're getting an anarchic,

下側頭葉皮質では

convulsive stimulation, or release,

その視覚細胞から

of all of these visual cells in the inferotemporal cortex.

無秩序で発作的な刺激や

放出が行われているのです

So, suddenly, you see a face. Suddenly, you see a car.

そして突然 顔や車が見えたり

Suddenly this and suddenly that.

色々なものが見えるのです

The mind does its best to organize

頭はまとめようとしたり

and to give some sort of coherence to this,

一貫性をもたせようと頑張りますが

but not terribly successfully.

完璧には働きません

When these were first described,

この幻覚が初めて発表されたとき

it was thought that they could be interpreted like dreams.

夢のように解釈できると思われていました

But, in fact, people say,

でも 患者さんは言う

"I don't recognize the people. I can't form any associations.

“こんな人たち知らない　関連づけ出来ないわ”

“カーミットなんて私にとって何の意味も持たない”

Kermit means nothing to me."

You don't get anywhere, thinking of them as dreams.

夢のように考えてもダメなんです

さぁ 私の話はこんなところです

Well, I've more or less said what I wanted.

I think I just want to recapitulate and say this is common.

要は この幻覚症状は

よくある事なんです

Think of the number of blind people.

世界の盲人数を考えてください

There must be hundreds of thousands of blind people

このような幻覚症状を持つ盲人は

who have these hallucinations

何十万といるに違いない

but are too scared to mention them.

でも怖くて言えないんです

So this sort of thing needs to be brought into notice,

ですから このような事実は患者 医者

世間のために もっと知られるべきなんです

for patients, for doctors, for the public.

Finally, I think they are infinitely interesting and valuable,

最後に これは

脳の働きを洞察するには 非常に興味深く

for giving one some insight as to how the brain works.

貴重な情報だと思っています

Charles Bonnet said, 250 years ago --

250年前にシャルルボネは

he wondered how, thinking of these hallucinations,

このような幻覚症状を思いながら

how, as he put it, the theater of the mind

脳の機械仕掛けから 心の劇作品が

could be generated by the machinery of the brain.

いかに作り出されるのだろうと考えました

Now, 250 years later,

250年経った現在 私たちは

I think we're beginning to glimpse how this is done.

真相を究明し始めた と思うのです

Thanks very much.

どうもありがとう

(Applause)

（拍手）

Chris Anderson: That was superb. Thank you so much.

最高だ どうもありがとう

You speak about these things with so much insight

洞察力が深くて 患者さんへの

and empathy for your patients.

共感が感じられました

Have you yourself experienced any of the syndromes you write about?

そのような経験を ご自身もされたことは？

Oliver Sacks: I was afraid you would ask that.

聞かれるだろうと思いましたよ

(Laughter)

（笑）

Well, yeah, a lot of them.

けっこう見ます

And, actually, I'm a little visually impaired myself.

実は私も視覚障害者です

I'm blind in one eye and not terribly good in the other.

片目は失明して もう片方も良好ではありません

And I see the geometrical hallucinations.

幾何学模様の幻覚が見えます

But they stop there.

他のは見えません

CA: And they don't disturb you?

不安にかられませんか？

Because you understand what's doing it, it doesn't make you worried?

どんなことが起きているのか分っておられるから

耳鳴りよりは ましです

OS: Well, they don't disturb me any more than my tinnitus,

which I ignore.

耳鳴りは無視してますけど

They occasionally interest me,

幻覚には時折興味が湧くので

and I have many pictures of them in my notebooks.

ノートにたくさん絵を描いています

I've gone and had an fMRI myself,

fMRIも使用して視覚野の

to see how my visual cortex is ticking over.

機能も見ました

And when I see all these hexagons

六角形や複雑な模様は

and complex things, which I also have,

眼性片頭痛でも

in visual migraine,

見ることがあるのですが

I wonder whether everyone sees things like this

これは普通なのでしょうかね

and whether things like cave art or ornamental art

そして洞窟壁画や装飾デザインは

may have been derived from them a bit.

幻覚をヒントに作られたのか興味があります

CA: That was an utterly, utterly fascinating talk.

非常に興味深い貴重な講話でした

Thank you so much for sharing.

どうもありがとうございました

OS: Thank you. Thank you.

ありがとうございました

(Applause)

（拍手）