Q-Eng

　　　　　　　　　　　　　　　　　　　　　　　　　　　 　　　　　　　　　　　　　　　　　　代表頁に戻る
始めと終りは易しいが医学説明は難しい。 睡眠の重要性で載せた。 日本語字幕参照。

このTED-Edでは、暗記などは３時間後,音楽練習などは１時間後に眠るのが良いとある。
（記憶後の睡眠効果は定説。 就寝までの時間は､調べたが諸説ありよくわからない｡）

難　　06分・・155wpm　　2015/02/11 新出

字幕：上の動画は開始後 で英語On/Off｡ 日本語選択､文字ｻｲｽﾞはｵﾌﾟｼｮﾝから｡
.　　　　　　　 （YouTubeは 日本語On/Off。 英語選択｡）

★下記英文はマウスオーバー辞書が使えます｡

It's 4 a.m., and the big test is in eight hours, followed by a piano recital. You've been studying and playing for days, but you still don't feel ready for either. So, what can you do? Well, you can drink another cup of coffee and spend the next few hours cramming and practicing, but believe it or not, you might be better off closing the books, putting away the music, and going to sleep.

Sleep occupies nearly a third of our lives, but many of us give surprisingly little attention and care to it. This neglect is often the result of a major misunderstanding. Sleep isn't lost time, or just a way to rest when all our important work is done. Instead, it's a critical function, during which your body balances and regulates its vital systems, affecting respiration（呼吸） and regulating everything from circulation to growth and immune response.

That's great, but you can worry about all those things after this test, right? Well, not so fast. It turns out that sleep is also crucial for your brain, with a fifth（5分の1）of your body's circulatory blood being channeled to it as you drift off. And what goes on in your brain while you sleep is an intensely active period of restructuring that's crucial for how our memory works.

At first glance, our ability to remember things doesn't seem very impressive at all. 19th century psychologist Herman Ebbinghaus demonstrated that we normally forget 40% of new material within the first twenty minutes, a phenomenon known as the forgetting curve.
　　Ebbinghaus ：エビングハウス（1850-1909） ドイツの心理学者、「忘却曲線」で有名

But this loss can be prevented through memory consolidation（記憶の固定）, the process by which information is moved from our fleeting short-term memory（短期記憶）to our more durable long-term memory（長期記憶）. This consolidation occurs with the help of a major part of the brain, known as the hippocampus（海馬）.

Its role in long-term memory formation was demonstrated in the 1950s by Brenda Milner in her research with a patient known as H.M. After having his hippocampus removed, H.M.'s ability to form new short-term memories was damaged, but he was able to learn physical tasks through repetition. Due to the removal of his hippocampus, H.M.'s ability to form long-term memories was also damaged.
　　Brenda Milner：ブレンダ・ミルナー（1918-） カナダの 先駆的 脳科学者（女性）

What this case revealed, among other things, was that the hippocampus was specifically involved in the consolidation of long-term declarative memory, such as the facts and concepts you need to remember for that test, rather than procedural memory, such as the finger movements you need to master for that recital.

Milner's findings, along with work by Eric Kandel in the 90's, have given us our current model of how this consolidation process works. Sensory data is initially transcribed and temporarily recorded in the neurons as short-term memory. From there, it travels to the hippocampus, which strengthens and enhances the neurons in that cortical area.

Thanks to the phenomenon of neuroplasticity（神経可塑性）, new synaptic buds are formed, allowing new connections between neurons, and strengthening the neural network where the information will be returned as long-term memory. So why do we remember some things and not others?

Well, there are a few ways to influence the extent and effectiveness of memory retention. For example, memories that are formed in times of heightened feeling, or even stress, will be better recorded due to the hippocampus' link with emotion.

But one of the major factors contributing to memory consolidation is, you guessed it, a good night's sleep. Sleep is composed of four stages, the deepest of which are known as slow-wave sleep（徐波睡眠）and rapid eye movement（レム、急速眼球運動）.
EEG（脳波図）machines monitoring people during these stages have shown electrical impulses moving between the brainstem（脳幹）, hippocampus(海馬）, thalamus（視床）, and cortex（皮質）, which serve as relay stations of memory formation. And the different stages of sleep have been shown to help consolidate different types of memories.
　　EEG ： Electroencephalogram　脳波図　（脳波は brain waves と言う）

During the non-REM slow-wave sleep（ノンレム徐波睡眠）, declarative memory is encoded into a temporary store in the anterior part（前部）of the hippocampus. Through a continuing dialogue between the cortex and hippocampus, it is then repeatedly reactivated, driving its gradual redistribution to long-term storage in the cortex.
REM sleep（レム睡眠）, on the other hand, with its similarity to waking brain activity, is associated with the consolidation of procedural memory.

So based on the studies, going to sleep three hours after memorizing your formulas and one hour after practicing your scales would be the most ideal.

So hopefully you can see now that skimping on sleep not only harms your long-term health, but actually makes it less likely that you'll retain all that knowledge and practice from the previous night, all of which just goes to affirm the wisdom of the phrase, "Sleep on it."
　　Sleep on it ： 「一晩眠ってじっくり考えよう｣　朝、頭がすっきりしたところで
　　　　　　　　　　 良案が浮かぶかもしれない という意味で使われる。

When you think about all the internal restructuring and forming of new connections that occurs while you slumber, you could even say that proper sleep will have you waking up every morning with a new and improved brain, ready to face the challenges ahead.