Scientists are providing a fuller understanding of the essential role that sleep plays in brain health, identifying an abrupt transition at about 2.4 years of age when its primary purpose shifts from brain building to maintenance and repair.
Researchers on Sept. 18 said they conducted a statistical analysis on data from more than 60 sleep studies. They looked at sleep time, duration of rapid eye movement (REM) sleep, brain size and body size, and devised a mathematical model for how sleep changes during development.
There are basically two types of sleep, each tied to specific brain waves and neuronal activity. REM, with the eyes moving quickly from side to side behind closed eyelids, is deep sleep with vivid dreams. Non-REM sleep is largely dreamless.
Photo: Reuters 照片：路透
During REM sleep, the brain forms new neural connections by building and strengthening synapses — the junctions between nerve cells, or neurons — that enable them to communicate, reinforcing learning and consolidating memories. During sleep, the brain also repairs the modicum of daily neurological damage it typically experiences to genes and proteins within neurons as well as clearing out byproducts that build up.
At about 2.4 years of age, the findings showed, sleep’s primary function changed from building and cutting connections during REM sleep to neural repair during both REM and non-REM sleep. “It was shocking to us that this transition was like a switch and so sharp,” said Van Savage, a UCLA professor of ecology and evolutionary biology and of computational medicine who is a senior author of the research published in the journal Science Advances.
REM sleep declines with age. Newborns, who can sleep about 16 hours daily, spend about 50 percent of their sleeping time in REM, but there is a pronounced drop-off at around 2.4 years. It drops to about 25 percent by age 10 and to about 10 percent to 15 percent around age 50. “Sleep is required across the animal kingdom and is nearly as ubiquitous as eating and breathing,” Van Savage said. “I’d say it is a pillar of human health.”(Reuters)
科學家近日提出更完整的理論，進一步闡釋睡眠對大腦健康扮演不可或缺的角色。科學家確認，兒童大腦約在二歲五個月時會發生突然的轉變。此時，睡眠的首要目的從大腦發育轉變成維護與修復。
研究人員於九月十八日指出，他們對超過六十個睡眠研究提供的資料進行統計學分析。他們觀察睡眠時間、快速動眼期的持續長度、大腦和身體尺寸，並且設計出一套數學模型，研究睡眠在成長過程中會如何發生變化。
基本上，睡眠分成兩種類型，各自和特定的腦波與神經元活動密切相關。在快速動眼期，眼球會在緊閉的眼皮後方快速左右移動，進入深層睡眠，此時做的夢也特別清晰。非快速動眼期則大多是無夢的。
在快速動眼期睡眠中，大腦藉由建立以及強化「突觸」──也就是神經細胞（或稱神經元）的相接處──形成新的神經連結，讓它們得以互相交流，藉此加深學習並且鞏固記憶。在睡眠期間，大腦也會修復平日受到的少量神經系統損傷──通常發生於基因和神經元裡面的蛋白質──同時清除累積的副產物。
研究顯示，在大約二歲五個月左右，睡眠的首要功能會發生改變，從快速動眼期睡眠中持續建立並且切斷連結，轉變成在快速動眼期以及非快速動眼期這兩個睡眠期間進行神經修復。這份研究近日發表於期刊《科學進展》，其資深作者范‧薩維奇指出：「我們很訝異，這個轉變就像是切換開關一樣，非常突然。」范‧薩維奇是美國加州大學洛杉磯分校生態學和演化生物學教授，同時也是計算醫學教授。
快速動眼期睡眠會隨著年紀增長而減少。新生兒一天可以睡到十六個小時，其中大約一半的睡眠時間都花在快速動眼期。然而，大概到兩歲五個月的時候，快速動眼期就會顯著降低。到了十歲，快速動眼期約佔睡眠時間的百分之二十五；到五十歲時，快速動眼期更衰退到睡眠時間的百分之十到十五左右。「睡眠在整個動物界都是必要的活動，就跟進食和呼吸一樣無所不在。」范‧薩維奇表示：「我會說，睡眠是人類健康的支柱。」（台北時報章厚明譯）
A: It’s a pity that I can’t go to Australian pop diva Kylie Minogue’s concert. B: Why not? A: Hit Japanese singer Kenshi Yonezu is staging two shows at the Taipei Arena this weekend, and I already bought tickets long ago. B: Wow, isn’t he one of the most popular Japanese singers in recent years? A: And Yonezu’s megahit “Lemon” topped the Billboard Japan Hot 100’s year-end chart in 2018 and 2019 consecutively. A: 我不能去澳洲歌后凱莉米諾的演唱會真可惜。 B: 為什麼？ A: 日本人氣歌手米津玄師週末將在小巨蛋熱唱兩場，我早早就買票啦。 B: 哇他可是日本近年來最紅的歌手之一。 A: 米津的神曲《Lemon》甚至還在2018、2019年連續稱霸告示牌日本單曲榜年度冠軍！ (By Eddy Chang, Taipei Times／台北時報張迪)
A: Australian pop diva Kylie Minogue is set to visit Taiwan for the third time on Saturday. B: I remember that her Taipei concerts in 2008 and 2011 caused a sensation, and I love her megahit “Can’t Get You Out of My Head.” A: This will be her first time performing in the southern city of Kaohsiung. B: Many music critics praise Kylie’s show as “a must-see in your lifetime.” A: Let’s go to Kaohsiung this weekend. A: 澳洲歌后凱莉米諾週六即將三度訪台。 B: 她曾在2008、2011年兩度在台北開唱都造成大轟動，我超愛她的神曲《Can’t Get You Out of My Head》。 A: 這次可是她首度唱進南台灣的高雄呢。 B: 許多樂評家說她的演唱會是「此生必看」！ A: 那我們週末去高雄吧。 （By Eddy Chang, Taipei Times／台北時報張迪）
Donburi, often simply called don, is a beloved Japanese dish that consists of a bowl of steamed rice topped with various other ingredients. The word donburi itself actually means “bowl” in Japanese, but it has come to represent much more than just a vessel. Donburi first emerged during the Edo period (1603–1867) as a quick and convenient meal for busy city dwellers. By the 19th century, donburi had become immensely popular among theater enthusiasts, who often purchased these portable meals to enjoy during long performances. Una-don, a donburi topped with grilled eel, was a particular favorite. Easy-to-carry and satisfying,
The Lemon Festival is a fun annual celebration in Menton, France. This festival began in 1934 and honors the region’s exceptional lemons. __1__ in February during the lemon season, the festival features beautiful floats and sculptures covered with dazzling lemons and oranges. These citrus creations are on display in the bright sunshine throughout the day, while at night, they are lit up and turn the town into a __2__ spectacle. The festival’s origins can be traced back to the late 19th century, when Menton was a major lemon producer. __3__, hotels would decorate their spaces with lemons and oranges
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