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: The 2025 World Masters Games will begin on May 17 and run until May 30. B: World Masters Games? A: It’s a quadrennial multi-sport event for people over 30, which will be jointly held by Taipei and New Taipei City. B: Cool, maybe we can go cheer for all the athletes from home and abroad. A: There will be an athletes’ parade in downtown Taipei prior to the opening ceremony on Saturday. Let’s go then. A: 2025雙北世界壯年運動會5月17日開幕，持續至5月30日閉幕。 B: 世壯運？ A: 這是四年一度、以30歲以上青壯年為主的運動會，本屆是由台北市和新北市共同舉辦。 B: 好酷喔，我們去幫來自國內外的選手們加油吧！ A: 週六在台北市區會有選手遊行，之後是開幕典禮，我們去看吧。 （By Eddy Chang, Taipei Times／台北時報張迪)
A: Where will the 35 sports of the 2025 World Masters Games be held? B: Apart from Taipei and New Taipei City, some games will take place in Yilan County, Taoyuan County, and Hsinchu County and City. A: The news says about 25,000 people, including many celebrities and sports stars, have already registered for the games. B: Even Taipei Mayor Chiang Wan-an, who is 47, registered for softball and squash. New Taipei Mayor Hou You-yi, who is 68, also registered for table tennis. A: And it will be the largest sports event ever in Taiwan’s history. How exciting. A:
Computex, Asia’s biggest electronics conference, kicked off Monday in Taipei, and as in years past drew industry chieftains from Nvidia Corp.’s Jensen Huang and Qualcomm Inc.’s Cristiano Amon to Young Liu of Foxconn, which makes the bulk of the world’s iPhones and Nvidia servers. But while last year’s event was a celebration of the post-ChatGPT AI boom, executives this time are likely grappling with the uncertainty of the Trump administration’s effort to reshape the global trade order — disrupting a decades-old model for tech manufacturing. This year’s exhibition will of course feature the hardware required to bring artificial intelligence to life.
Dog owners often wish they could understand their pets’ thoughts. “Dog buttons” might turn their dream into a reality. These specially designed buttons, __1__ sound chips, enable dogs to communicate their needs by pressing buttons corresponding to pre-recorded words like “walk,” “play,” “outside,” and “food.” This bridges the communication __2__ between humans and their canine companions. The science behind dog buttons is based on the concept of associative learning. It’s a process __3__ learners can link actions with outcomes. For instance, if an owner consistently presses the “walk” button and then takes their dog for a walk, the dog
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