 Even facts "forgotten" by people during a busy day may be retrieved if this is followed by a good night's sleep.
Researchers from the University of Chicago asked volunteers to remember simple words. Many found their memories letting them down towards the end of the day, but the following morning, those who had slept well could recall much more. Researchers, writing in the journal Nature, said the brain could "rescue" lost memories during the night. When the brain is first asked to remember something, that memory is laid down in an "unstable" state, meaning that it is possible that it could be lost. At some point, the brain consolidates those it deems important into a "stable", more permanent state. However, the Chicago researchers suggested that it was possible for a "stable" memory to be made "unstable" again. This would mean that memories could be modified then filed away again in the face of new experiences. The 12 volunteers tested in the experiment were played words created through a speech synthesizer which were purposely difficult to understand. Initially, the written version of the word was available, but afterwards the volunteers were asked to identify the word from the audio version only. Tests revealed that the ability to recall the right word tended to tail off as the day ended. However, when the volunteers were retested after a good night's sleep, they were able to recall some words that they had "forgotten" the previous evening. Dr Daniel, one of the study authors, said: "Sleep consolidates memories, protecting them against subsequent interference or decay. "Sleep also appears to 'recover' or restore memories." He said: "If performance is reduced by decay, sleep might actively recover what has been lost." Dr Karim Nader, from the Department of Psychology in McGill University in Montreal, said: "Memory research is undergoing a transformation - no longer is memory thought to be a hard-wiring of the brain, instead it seems to be a process of storage and re-storage. "Sleep helps some memories 'mature' and also prunes out unimportant memories." (Agencies) | 如果晚上睡個好覺，即使白天由于忙碌而“遺忘”的一些事情也可以重新回憶起來。 芝加哥大學的研究者們要求志愿者們記住一些簡單的單詞。 到了晚上，許多人對自己的記憶力都感到失望。但是第二天早晨，那些睡得好的人能回想起來更多的單詞。 研究者們在《自然》雜志發表論文說：大腦可以在晚間“修復”失去的記憶。 當大腦最初被要求記住一些東西時，那段記憶處于一種“不穩定的”狀態，這意味著它很可能會丟失。 在有些時刻，大腦會將那些它認為重要的記憶強化為“穩定的”狀態，也就是更持久的狀態。 然而，芝加哥大學的研究者們提示說“穩定的”記憶也可能會轉變為“不穩定的”。 這就意味著當遇到新的情況時，記憶可能會被修改，隨后重新排列。 參加試驗的12名志愿者收聽了通過語音合成器產生的特別難懂的單詞。 剛開始還給志愿者提供單詞腳本，但是后來就要求他們僅僅通過聲音來辨別單詞。 實驗顯示：一天快結束的時候，準確回憶單詞的能力隨之減弱。 然而，當志愿者們睡了個好覺過后再次接受測試的時候，他們能夠回憶起一些他們前一天晚上已經"遺忘"的單詞。 這篇論文的一位作者丹尼爾博士說：“睡眠可以鞏固記憶，防止它們隨后受到干擾或衰減。 “睡眠看來也可以恢復記憶。” 他說：“如果記憶功能因為衰減而降低，睡眠可以有效的恢復丟失的記憶。” 蒙特利爾市麥基爾大學心理學系的卡里姆·納德博士說：“記憶力研究正在轉型——記憶不再被認為是大腦的硬件，而似乎是一個儲存和再儲存的過程。 “睡眠使某些記憶變得‘成熟’，同時也刪掉了那些不重要的記憶。” （中國日報網站譯） |
Updated: 2003-10-10 01:00
