Name: 【TED-Ed】腦部掃描是怎麼運作的？(How do brain scans work? - John Borghi and Elizabeth Waters)
Uploaded: 2018-05-18T04:23:26.000Z
Duration: 5 min

進階形容詞比較級句型

反身代名詞

there's only one thing in our solar system sophisticated enough to study itself:

But this self-investigation  is incredibly challenging;

a living brain is shielded  by a thick skull,

但這自我探索的挑戰性非常高：

活體大腦被很厚的顱骨保護著，

and made up of billions of tiny, connected cells.

That's why it's so difficult to isolate,  observe, and understand diseases

且大腦由數億細小、 互相連接的細胞所組成

因此，我們很難分離、 觀察並瞭解疾病

So how do we study living brains  without harming their owners?

We can use a trio of techniques  called EEG,

那我們要如何研究活體大腦 而不傷害它的主人呢？

我們能用三種技術， 分別叫 EEG、

Each measures something different  and has its own strengths and weaknesses,

它們測量的東西不同， 且各有優缺點，

which measures electrical  activity in your brain.

首先是 EEG ，又稱「腦電圖」，

As brain cells communicate,  they produce waves of electricity.

Electrodes placed on the skull pick up these waves,

腦細胞傳送訊息時會製造電波，

and differences in the signals detected  between electrodes

provide information  about what's happening.

This technique was invented  almost 100 years ago,

能提供資訊，看發生什麼事了。

and it's still used to diagnose conditions like epilepsy and sleep disorders.

It's also used to investigate what areas  of the brain are active

至今仍被使用在鑑別診斷上， 如癲癇和睡眠障礙；

it can measure changes that occur  in just milliseconds.

exactly where any particular  pattern originates.

Electrical signals are generated  constantly all over the brain

它很難精準定位 特定波型特徵的來源。

and they interact with each other to produce complex patterns.

Using more electrodes or sophisticated  data-processing algorithms can help.

而大腦用此方式傳遞訊息， 製造出複雜的波型特徵。

But in the end, while EEG can tell you  precisely when certain activity occurs,

用更多電極，或建立複雜函數 來解讀檔案有幫助，

但最後，僅管 EEG 能告訴你 特定活動何時產生，

To do that, you'd need another technique,

such as functional magnetic  resonance imaging, or fMRI.

fMRI measures how quickly oxygen  is consumed by brain cells.

例如「功能性磁振造影」， 又稱 fMRI 。

Active areas of the brain use oxygen more quickly.

fMRI 偵測腦細胞 消耗氧氣的速率，

So watching an fMRI scan while a person completes cognitive or behavioral tasks

can provide information about which  regions of the brain might be involved.

因此當某人完成認知 或行為上的任務時，

That allows us to study everything from how we see faces

fMRI 可以提供大腦哪些部分 參與任務的資訊。

這使我們能研究所有事情， 從如何觀察人臉

fMRI can pinpoint differences in brain activity to within a few millimeters,

but it's thousands  of times slower than EEG.

fMRI 能定位腦部活動， 其精準度在數毫米間，

can help show when, and where, neural activity is occurring.

The third, even more precise, technique is called positron emission tomography

能幫助我們了解，神經活動 開始的時間和位置。

and it measures radioactive elements  introduced into the brain.

第三個技術則更精確，叫做 「正子發射斷層掃描（ PET ）」，

That sounds much scarier  than it actually is;

它能測量事先注入 大腦的放射性物質，

PET scans, like fMRI and EEG,  are completely safe.

During a PET scan, a small amount of radioactive material called a tracer

然 PET 跟 fMRI 和 EEG 一樣 完全安全。

在 PET 掃描期間，少量 放射線物質稱作示蹤劑

and doctors monitor its circulation through the brain.

By modifying the tracer to bind to specific molecules,

researchers can use PET to study  the complex chemistry in our brains.

透過修改示蹤劑來結合特定分子，

It's useful for studying  how drugs affect the brain

研究者可以用 PET 來研究 腦部複雜的化學分子。

But this technique has  the lowest time resolution of all

及偵測疾病如阿茲海默症上，這很有用。

because it takes minutes for the tracer  to circulate and changes to show up.

These techniques collectively  help doctors and scientists

因為要數分鐘，示蹤劑才會 流到腦部，變化才會顯現。

connect what happens in the brain with our behavior.

這些科技共同幫助醫師和科學家了解，

But they're also limited  by how much we still don't know.

行為和大腦發生的事 如何連結起來，

For example, let's say researchers are interested in studying how memory works.

但它們也受到我們知識有限的限制，

After asking 50 participants to memorize  a series of images while in MRI scanners,

例如，研究者想知道記憶如何運作，

the researchers might analyze the results

使用 fMRI ，在問過五十個 受試者記下一系列的圖片後，

and discover a number  of active brain regions.

Making a link between memory  and specific parts of the brain

to better understand  what's happening in each region,

and whether the activity is because  of their involvement in memory

or another process  occurring simultaneously.

More advanced imaging  and analysis technology

might one day provide  more accurate results

有天或許能提供更準確的結果，

Until then, our brains will keep measuring, analyzing, and innovating

或甚至區分個別神經元的活動。

在那之前，我們的大腦會 繼續測量、分析和創新，

one of the most remarkable things  we've ever encountered.

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【TED-Ed】腦部掃描是怎麼運作的？(How do brain scans work? - John Borghi and Elizabeth Waters)

constantly

specific

cognitive

individual