Uncovering the brain's biggest secret - Melanie E. Peffer

譯者: HSIAO-WEN HUANG 審譯者: Helen Chang

In the late 1860s, scientists believed they were on the verge

在1860年代晚期

科學家們深信

of uncovering the brain’s biggest secret.

已在解答大腦最大秘密的邊緣

They already knew the brain controlled the body through electrical impulses.

他們已知道大腦如何控制電脈衝

The question was, how did these signals travel through the body

但問題是

這些訊號如何經在身體中傳遞

without changing or degrading?

而並未改變或遞減的呢？

It seemed that perfectly transmitting these impulses

看似這些完美傳遞的脈衝

would require them to travel uninterrupted along some kind of tissue.

必須不間斷地經過一些組織

This idea, called reticular theory,

這個想法

被稱為「網狀理論」

imagined the nervous system as a massive web of tissue

假想神經系統是一個巨大的網狀組織

that physically connected every nerve cell in the body.

實體連接身體中每個神經細胞

Reticular theory captivated the field with its elegant simplicity.

網狀理論以簡單易懂在此領域聞名

But soon, a young artist would cut through this conjecture,

然而很快地

有位年輕的藝術家推翻了這個推論

and sketch a bold new vision of how our brains work.

並且還大膽地勾勒出 大腦如何運作的新想法

60 years before reticular theory was born,

網狀理論產生的60年前

developments in microscope technology

蓬勃發展的顯微鏡科技

revealed cells to be the building blocks of organic tissue.

揭開細胞是有機組織的基本構造單位

This finding was revolutionary,

在當時是革命性的發現

but early microscopes struggled to provide additional details.

但是早期的顯微鏡 很難再進一步提供更多訊息

The technology was especially challenging for researchers studying the brain.

該技術對大腦研究人員極具挑戰性

Soft nervous tissue was delicate and difficult to work with.

軟組織特別脆弱，難以研究

And even when researchers were able to get it under the microscope,

即使研究員能夠將其放到顯微鏡下

the tissue was so densely packed it was impossible to see much.

這些組織會密集聚在一起

難以觀察

To improve their view,

為了改善視野

scientists began experimenting with special staining techniques

科學家們開始實驗特別的染色技術

designed to provide clarity through contrast.

以獲得更好的對比解析度

The most effective came courtesy of Camillo Golgi in 1873.

最有效的方式是來自於 卡米洛 .高耳基在1873年

First, Golgi hardened the brain tissue with potassium bichromate

首先

高爾基使用二鉻酸鉀將腦部組織硬化

to prevent cells from deforming during handling.

目的是為了預防操作過程中組織變形

Then he doused the tissue in silver nitrate,

接著

他使用硝酸銀點在組織上

which visibly accumulated in nerve cells.

使得神經細胞可以被清楚地看見

Known as the “black reaction,”

被稱作「黑化反應」

Golgi’s Method finally allowed researchers to see the entire cell body

高爾基的方法最終使研究者 能夠看見完整的細胞體

of what would later be named the neuron.

之後被稱作「神經細胞」

The stain even highlighted the fibrous branches

這些染色甚至加強標示了纖維狀的分支

that shot off from the cell in different directions.

從細胞四散至不同方向

Images of these branches became hazy at the ends,

這些分支的影像在末端變得朦朧

making it difficult to determine exactly how they fit into the larger network.

很難精準確定 它們在神經網絡扮演的角色

But Golgi concluded that these branches connected,

但是高爾基得出結論 這些分支彼此連結

forming a web of tissue comprising the entire nervous system.

形成網狀的組織 最終完整形成神經系統

14 years later, a young scientist and aspiring artist

14年之後

有位年輕有抱負的科學家兼藝術家

named Santiago Ramón y Cajal began to build on Golgi’s work.

名為桑地牙哥·拉蒙卡哈 以高爾基的成果為基礎開始研究

While writing a book about microscopic imaging,

當撰寫有關顯微鏡成像時

he came across a picture of a cell treated with Golgi’s stain.

他看見高爾基染色細胞的圖片

Cajal was in awe of its exquisite detail— both as a scientist and an artist.

卡哈對於這些細緻的細節非常驚嘆

對於科學家及藝術家皆然

He soon set out to improve Golgi’s stain even further

他迅速開始改善高爾基染色方式

and create more detailed references for his artwork.

並且創造更多細節來佐證他的藝術作品

By staining the tissue twice in a specific time frame,

藉由在特定時間內染色兩次的方式

Cajal found he could stain a greater number of neurons with better resolution.

卡哈發現能將更多神經細胞染色 染得還更清楚

And what these new slides revealed would upend reticular theory—

然而這些新玻片發明將打破網狀假說

the branches reaching out from each nerve cell

當分支從每個神經細胞四散

were not physically connected to any other tissue.

並不會與其他組織連結

So how were these individual cells transmitting electrical signals?

那麽個別細胞是如何 傳遞電位訊號的呢？

By studying and sketching them countless times,

藉由無數次研讀及推測

Cajal developed a bold, new hypothesis.

卡哈發展出一個大膽、全新的假說

Instead of electrical signals traveling uninterrupted across a network of fibers,

並非電位訊號藉由不間斷的連結 傳遞至纖維細胞網絡

he proposed that signals were somehow jumping from cell to cell

他提議訊號是藉由跳躍 從一個細胞至另一個細胞

in a linear chain of activation.

藉由一連串的活化

The idea that electrical signals could travel this way was completely unheard of

電位訊號藉由這樣方式傳遞 在當時是前所未聞的

when Cajal proposed it in 1889.

當卡哈在1889年提出時

However his massive collection of drawings supported his hypothesis from every angle.

然而他大量的作品 從每個角度支持他的假說

And in the mid-1900s, electron microscopy further supported this idea

在1900年代中期

電子顯微鏡更進一步支持這項想法

by revealing a membrane around each nerve cell

藉由透露每個神經細胞是 被細胞膜包圍的

keeping it separate from its neighbors.

使其和鄰間細胞分開

This formed the basis of the “neuron doctrine,”

這成就了「神經元學說」的基礎

which proposed the brain’s tissue was made up of many discrete cells,

這項說明了腦部組織是由 許多分散的細胞組成的

instead of one connected tissue.

而非一個連結的組織

The neuron doctrine laid the foundation for modern neuroscience,

神經元學說成就了現今的神經科學

and allowed later researchers to discover that electrical impulses

也使後來的研究者 進一步探究神經脈衝

are constantly converted between chemical and electrical signals

是在化學及電位訊號中不間斷地轉換

as they travel from neuron to neuron.

當他們移動從一個細胞至一個細胞時

Both Golgi and Cajal received the Nobel Prize

高爾基和卡哈皆獲得了諾貝爾獎

for their separate, but shared discoveries,

因為他們分別但是共同的發現

and researchers still apply their theories and methods today.

並且現在的研究者依然使用 他們的理論和方式

In this way, their legacies remain connected as discrete elements

這麼一來

他們的傳奇雖然分散但仍然相連

in a vast network of knowledge.

在這個諾大的知識網絡裡