時差N小時:選擇性記憶
雅艾爾：你有過不愉快的記憶嗎，唐?
Don: Sure. Who doesn't?
唐：當(dāng)然。誰都會有。
Yael: What would you say to having thempermanently erased from your brain?
雅艾爾：如果把它們從大腦里永久得清除，你會怎么看?
Don: Without losing other memories?
唐：不會喪失其它記憶嗎?
Yael: Right. Scientists did just that with rats. They trained rats to fear two different sounds bysending a mild electric shock through the rats' paws when they played the sounds. ThisPavlovian technique resulted in the rats freezing up in nervous anticipation of the shocksevery time they heard either sound. Scientists wanted to know whether they could erase one ofthe memories without erasing the other one, even though both sounds result in the same fear.
雅艾爾：對?？茖W(xué)家對老鼠做過這樣的實(shí)驗(yàn)。當(dāng)他們彈奏音樂時，科學(xué)家使溫和的電流震動傳送到它們的爪子，以這種方式訓(xùn)練老鼠害怕兩種不同的聲音。這種巴普洛夫的技術(shù)導(dǎo)致老鼠每次聽到其中一種聲音就因害怕點(diǎn)電擊而緊張地發(fā)抖?？茖W(xué)家想知道在兩種聲響同樣使它們恐懼的前提下，它們是否能夠在消除一種記憶的同時而不喪失另一種記憶。
Don: I didn't know scientists knew how to erase memories at all.
唐：我一點(diǎn)都不認(rèn)為科學(xué)家們知道怎么去除記憶。
Yael: They do. You see, long-term memories aren't nearly as solid as we like to think. They'reactually very fragile. Every time we recall a long-term memory, it becomes malleable. Justbefore playing one of the sounds, scientists injected half the rats with a chemical that interfereswith memory reconsolidation. Thus, when they were in the process of remembering whataccompanies the sound, the drug went to work.
雅艾爾：他們知道。顯而易見，長期性記憶并非我們想象的那么牢固。每當(dāng)我們回憶一段長期記憶時，它就會繼續(xù)延展。在播放其中任一種聲音之前，科學(xué)家們給一半的老鼠注射了干擾記憶的化學(xué)物質(zhì)。這樣，在老鼠回憶伴隨聲音所發(fā)生的事情時，這種藥物就會起作用。
Don: Then what?
唐：那又怎么樣?
Yael: When they played both sounds a day later, the rats that had been injected with thechemical did not freeze up when they heard the sound that had accompanied the drug. Theyfroze as usual when they heard the second sound.
雅艾爾：一天后科學(xué)家再次播放這兩種聲音，當(dāng)被注射藥物的老鼠聽到注射時的聲音后沒有表現(xiàn)出害怕。但聽到第二種聲音時還是像往常一樣呆住了。
Don: They had forgotten to be afraid. Hmm. This business makes me kind of nervous.
唐：他們忘記了害怕。嗯。這個實(shí)驗(yàn)聽起來有點(diǎn)恐懼。
Yael: I know what you mean, but for people with post-traumatic stress disorder, selectivememory erasure could prove enormously useful.
雅艾爾：我明白你的想法，但選擇性記憶對于患上創(chuàng)傷后精神失調(diào)的人有很大的幫助。
Don: True. I guess some fears are best laid to rest.
唐：那倒是真的。我認(rèn)為有的恐懼最好將它埋葬掉。
