電休克療法幫患者忘卻痛苦記憶

Scientists have zapped an electrical current to people's brains to erase distressing memories, part of an ambitious quest to better treat ailments such as mental trauma, psychiatric disorders and drug addiction.

近期研究發現，向腦中輸入電流可以抹去人們不愉快的記憶。這是科學家在更好地治療心理創傷、精神疾病和藥物成癮等疾病的研究過程中邁出的又一步。

In an experiment, Patients were first shown a troubling story, in words and pictures. A week later they were reminded about it and given electroconvulsive therapy, formerly known as electroshock. That completely wiped out their recall of the distressing narrative.

在一項試驗中，科學家首先藉助文字和圖片向患者呈現一則令人煩惱的故事。一週之後，科學家會提醒患者回憶這個故事，然後對患者實施電休克治療（即人們熟知的電擊療法），結果是患者完全忘記了這個痛苦的故事。

'It's a pretty strong effect. We observed it in every subject,' said Marijn Kroes, neuroscientist at Radboud University Nijmegen in the Netherlands and lead author of the study, published Sunday in the journal Nature Neuroscience.

荷蘭奈梅亨拉德伯德大學(Radboud University Nijmegen)神經科學家克勒斯(Marijn Kroes)說：效果非常明顯，我們在所有受試者中都觀察到了這一效果。克勒斯是這篇研究論文的主筆，論文週日發表在《自然神經科學》(Nature Neuroscience)雜誌上。

The experiment recalls the plot of the movie 'Eternal Sunshine of the Spotless Mind,' where an estranged couple erases memories of each other.

這項試驗讓人想起《美麗心靈的永恆陽光》(Eternal Sunshine of the Spotless Mind)這部電影，影片中一對感情不合的情侶抹除了彼此的記憶。

Science has tinkered with similar notions for years. In exposure treatment, repetitive exposure to a phobia in a nonthreatening way is designed to help patients confront their fears and gradually weaken the fear response, a process known as extinction. Some researchers also are experimenting with antianxiety drug propranolol. The hope is that one day it may be possible to selectively eliminate a person's unwanted memories or associations linked to smoking, drug-taking or emotional trauma.

科學界多年來也一直在進行相關研究。在暴露療法中，醫生以一種不具威脅性的方式讓患者頻繁暴露於所恐懼的事物中，幫助他們直面內心的恐懼並逐漸弱化其恐懼反應，這個過程被稱作“消退法”(extinction)。一些研究人員還對抗焦慮藥物“心得安”(propranolol)進行試驗，希望有朝一日能選擇性地篩除人們不想保留的記憶，或是與吸菸、吸毒或情感創傷聯繫在一起的記憶。

Scientists used to think that once a memory took hold in the brain, it was permanently stored and couldn't be altered. People with anxiety disorders were taught to overcome their fears by creating a new memory. Yet the old memory remained and could be reactivated at any time.

科學家們曾經認爲，一段記憶一旦印在腦子裏就會永久保存下去而無法更改。過去，治療焦慮症患者的辦法是讓他們創造新的記憶以克服恐懼。然而舊的記憶保存不動，並可能隨時被重新激發出來。

About a decade ago, scientists made a surprising discovery. They showed that when a lab rodent was given a reminder of some past fear, the memory of that event appeared to briefly become unstable. If nothing was done, that memory stabilized for a second time, and thus got ingrained-a process known as reconsolidation.

大約在10年前，科學家有了一個意外的發現。當提醒實驗室中的齧齒類動物回憶過去的恐懼場景時，腦中的那段回憶會暫時呈現出不穩定狀態。如果不採取措施，那段記憶會再一次穩定下來，並深植於腦中，這一過程被稱作“再鞏固”(reconsolidation)。

But when certain drugs, known to interfere with the reconsolidation process, were injected directly into the rodent's brain, they wiped out the animal's fearful memory altogether. Crucially, other memories weren't erased.

但如果將某些可以干擾“再鞏固”過程的藥物直接注射進齧齒動物的腦中，動物的恐懼記憶會被徹底抹除。而且關鍵在於，其他記憶並沒有被抹去。

Whether it was possible to disrupt the memory-consolidation process in humans was thought to be difficult to answer because injecting drugs into the human brain is risky business. Dr. Kroes and his colleagues found a way around the problem.

至於能否對人腦的“再鞏固”過程進行干預，則被認爲是一個很難回答的問題，因爲向人腦中注射藥物風險較大。克勒斯和他的同事們找到了一種可以繞開這個問題的辦法。

Their test subjects were 39 patients who were undergoing electroconvulsive therapy, for severe depression. In ECT treatment, patients get a muscle relaxant and an anesthetic and an electrical current is passed to part of their brains, triggering a brief seizure that can help treat the depression. It isn't clear how the technique works: Some scientists have suggested it changes the pattern of blood flow or metabolism in the brain, while others believe it releases certain chemicals in the brain that battle the depression.

他們的試驗對象是39名因患有嚴重抑鬱症而接受電擊治療的患者。在電擊治療中，醫生給患者使用肌肉鬆弛劑和麻醉劑，並讓電流通過患者大腦的部分區域，電流可引發疾病短時間突然發作，有助於治療抑鬱症。人們還不清楚這種療法的原理，一些科學家猜測是電流改變了血流模式或大腦的新陳代謝，還有人相信是電流促使腦部釋放出某些可以抗擊抑鬱症的化學物質。

Patients who are treated with ECT are those who typically haven't responded to an array of other treatments, including the most powerful drugs available.

接受電療的患者通常都是在試用了各種其他治療方法均不見效（包括最強力的藥物）後轉而接受該治療的。

A lot more work needs to be done. It isn't clear whether the memory erasure is temporary or permanent. And while the technique might work for simple stories, it needs to be shown that it also works for real-world traumatic memories.

這項工作還遠沒有完成。科學家還不清楚這種記憶抹除是暫時還是永久性的。而且，儘管這一技術在抹去簡單故事的記憶方面可能有效，但科學家還需要證明它能夠讓人忘記真實世界中的悲慘經歷。

Some researchers looking to move beyond ECT are now also experimenting with propranolol, which inhibits the actions of a hormone that enhances memory consolidation. This summer, Karim Nader, a neuroscientist at McGill University in Canada, hopes to test the drug in about 50 patients suffering from post-traumatic stress disorder.

一些研究人員力圖研發出較電休克療法更好的治療辦法，他們正在對心得安進行試驗，這種藥物可抑制一種強化鞏固記憶的荷爾蒙的活動。加拿大麥吉爾大學(McGill University)的神經科學家納德爾(Karim Nader)希望在明年夏天能夠請到約50名有創傷後應激障礙的病人蔘與測試這一藥物。