published an astonishing report about a 29-year-old builder.

1995 年，英國醫學期刊刊出了

He accidentally jumped onto a 15-centimeter nail,

一篇關於一名二十九歲 建築工人的驚人報告。

which pierced straight through his steel-toed boot.

他意外跳到了一根 十五公分的釘子上，

He was in such agonizing pain that even the smallest movement was unbearable.

釘子直接穿過了他的鋼頭靴。

But when the doctors took off his boot, they faced a surprising sight:

他非常痛苦，連最小的 動作都無法忍受。

the nail had never touched his foot at all.

但當醫生取下他的靴子時， 他們看到的景象讓他們驚呆了：

For hundreds of years,

釘子根本沒有碰到他的腳。

scientists thought that pain was a direct response to damage.

數百年來，

By that logic, the more severe an injury is, the more pain it should cause.

科學家認為疼痛是 對於損傷的直接反應。

But as we've learned more about the science of pain,

根據這樣的邏輯，越嚴重的傷 會造成越大的疼痛。

we've discovered that pain and tissue damage don't always go hand in hand,

但，隨著我們對疼痛的 科學有更多的了解，

even when the body's threat signaling mechanisms are fully functioning.

我們發現，疼痛和組織損傷 不見得是一致相符的，

We're capable of experiencing severe pain out of proportion to an actual injury,

即使身體的威脅信號機制 完全正常運作亦然。

and even pain without any injury,

我們能夠經歷到和實際傷口 不成比例的劇烈疼痛，

like the builder, or the well-documented cases of male partners

甚至可能在沒受傷時感到疼痛，

of pregnant women experiencing pain during the pregnancy or labor.

就像那位建築工人， 或是有許多文件記載的案例，

What's going on here?

懷孕女性在懷孕過程或分娩時，

There are actually two phenomena at play:

男性伴侶也會經歷到疼痛。

the experience of pain, and a biological process called nociception.

這是怎麼回事？

Nociception is part of the nervous system's protective response

其實，這背後有兩種現象：

to harmful or potentially harmful stimuli.

對疼痛的體驗以及一種 生物過程，叫做痛覺。

Sensors in specialized nerve endings

神經系統會對於有害或可能 有害的刺激產生保護性反應，

detect mechanical, thermal, and chemical threats.

而痛覺是反應的一部分。

If enough sensors are activated,

專門的神經末端的感測器

electrical signals shoot up the nerve to the spine and on to the brain.

會偵測機械的、溫度的， 及化學的威脅。

The brain weighs the importance of these signals

如果有足量的感測器被觸發，

and produces pain if it decides the body needs protection.

電訊號就會透過神經 傳到脊椎，再傳到大腦。

Typically, pain helps the body avoid further injury or damage.

大腦會判斷這些訊號的重要性，

But there are a whole set of factors besides nociception

如果它覺得身體需要保護， 便會產生疼痛。

that can influence the experience of pain— and make pain less useful.

疼痛通常協助身體 避免進一步受傷或受損。

First, there are biological factors that amplify nociceptive signals to the brain.

但除了痛楚之外，有一整組因子

If nerve fibers are activated repeatedly,

都有可能影響到疼痛的體驗—— 讓疼痛變得不那麼有用。

the brain may decide they need to be more sensitive

首先，有生物因子， 會放大發送到大腦的痛覺訊號。

to adequately protect the body from threats.

如果神經纖維不斷重覆被觸發，

More stress sensors can be added to nerve fibers

大腦可能會判斷它們得要更敏感些，

until they become so sensitive that even light touches to the skin

才能夠妥當地保護身體不受威脅。

spark intense electrical signals.

會有更多壓力感測器 被加到神經纖維上，

In other cases,

直到神經纖維變得非常敏感， 即使輕輕一碰到皮膚

nerves adapt to send signals more efficiently, amplifying the message.

也會發出強烈的電訊號。

These forms of amplification

在其他的情況中，神經會適應，

are most common in people experiencing chronic pain,

以更有效地發送訊號， 將訊息放大。

which is defined as pain lasting more than 3 months.

這些放大的形式

When the nervous system is nudged into an ongoing state of high alert,

最常在長期疼痛的人身上看到，

pain can outlast physical injury.

長期疼痛指的是持續 超過三個月的疼痛。

This creates a vicious cycle in which the longer pain persists,

當神經系統進入了 持續高度警戒的狀態，

the more difficult it becomes to reverse.

疼痛可能會持續得比傷口還久。

Psychological factors clearly play a role in pain too,

這會造成惡性循環， 痛苦持續越久，

potentially by influencing nociception and by influencing the brain directly.

它就越難反轉。

A person's emotional state, memories,

很明顯，心理因子也和疼痛有關，

beliefs about pain and expectations about treatment

它有可能會影響痛覺 以及直接影響大腦。

can all influence how much pain they experience.

人的情緒狀態、記憶、

In one study,

有多相信疼痛，以及對治療的預期

children who reported believing they had no control over pain

都有可能會影響他們 體驗到的疼痛程度。

actually experienced more intense pain

在一項研究中，認為自己 無法控制痛苦的孩子

than those who believed they had some control.

會經歷到更強烈的疼痛，

Features of the environment matter too:

而相信能控制疼痛的人 就沒這麼嚴重。

In one experiment,

環境的特徵也很重要：

volunteers with a cold rod placed on the back of their hand

在一項實驗中，

reported feeling more pain when they were shown a red light than a blue one,

將一根冰冷的桿子 放在自願者的手背上，

even though the rod was the same temperature each time.

當他們看到紅燈時，所回報的 疼痛度就高於看到藍燈時，

Finally, social factors like the availability of family support

但桿子的溫度一直都沒有變過。

can affect perception of pain.

最後是社會因子， 比如是否能取得家人支持

All of this means that a multi-pronged approach to pain treatment

就可能影響對痛苦的感知。

that includes pain specialists, physical therapists, clinical psychologists, nurses

上述這些意味著， 在治療疼痛時若能多管齊下，

and other healthcare professionals is often most effective.

配合疼痛專家、物理治療師、 臨床心理學家、護士，

We're only beginning to uncover the mechanisms behind the experience of pain,

及其他健康照護專業人士， 會有最好的效果。

but there are some promising areas of research.

我們才剛開始發掘 感受疼痛背後的機制，

Until recently,

但有一些研究領域的前景看好。

we thought the glial cells surrounding neurons were just support structures,

到最近之前，

but now we know they have a huge role in influencing nociception.

我們都認為神經周圍的膠質細胞 只是支撐用的結構，

Studies have shown that disabling certain brain circuits in the amygdala

但現在我們知道它們在影響痛覺 方面，扮演重要的角色。

can eliminate pain in rats.

研究顯示，關閉 杏仁核中的某些腦迴路

And genetic testing in people with rare disorders

就可以消除老鼠的疼痛。

that prevent them from feeling pain

針對無法感受疼痛的特殊疾病病人

have pinpointed several other possible targets for drugs

所做的基因檢測

and perhaps eventually gene therapy.

找出了數個可能的用藥方向，