進入寒冷的冬季，很多人都有早上起床困難的問題。不管鬧鐘響了幾次，總是感覺睡不醒，“被窩裡面好暖好舒服，哪裡都不想伸出來。”
這是咋回事兒？難道一到冬天，人也會像有些動物一樣需要冬眠嗎？今天我們就從科學角度詳細說說，為什麼冬天起床更困難。
A study conducted by neurobiologists from Northwestern University made it possible to elucidate the mechanisms underlying this phenomenon.
美國西北大學神經生物學家進行的一項研究或許能解釋導致這種現象的機理。
Their study on fruit flies, has found a thermometer circuit can transfer information about cold temps from their antennas right to the brain.
他們在對果蠅的研究中發現了一個溫度提示迴路，可以將低溫資訊從觸角傳輸到大腦。
They show how, through this circuit, seasonally cold and dark conditions can inhibit neurons within the fly brain that promote activity and wakefulness, particularly in the morning.
研究顯示，透過該回路，季節性寒冷和黑暗環境可以抑制果蠅大腦中促進活動和清醒的神經元，特別是在早晨。
“This helps explains why -- for both flies and humans -- it is so hard to wake up in the morning in winter,” said Marco Gallio, associate professor of neurobiology in the Weinberg College of Arts and Sciences. “By studying behaviors in a fruit fly, we can better understand how and why temperature is so critical to regulating sleep.”
溫伯格文理學院神經生物學副教授馬可·加利奧表示：“這有助於解釋為什麼無論對蒼蠅還是人類來說，在冬天的早上醒來都很困難。透過研究果蠅的行為，我們可以更好地理解溫度對調節睡眠的重要性。”
[Photo/Pexels]
The study, led by Gallio and conducted in Drosophila melanogaster, was published in the journal Current Biology.
這項研究由加利奧主導，研究物件為黑腹果蠅，研究成果發表在《當代生物學》雜誌上。
The paper describes for the first time “absolute cold” receptors residing in the fly antenna, which respond to temperature only below the fly’s “comfort zone” of approximately 77 degrees Fahrenheit.
這篇論文首次介紹了果蠅觸角中的“絕對寒冷”感覺神經元，它們只對低於果蠅溫度舒適區的氣溫作出反應。果蠅感到適宜的溫度接近25攝氏度。
Having identified those neurons, the researchers followed them all the way to their targets within the brain. They found the main recipients of this information are a small group of brain neurons that are part of a larger network that controls rhythms of activity and sleep. When the cold circuit they discovered is active, the target cells, which normally are activated by morning light, are shut down.
在識別出這些神經元后，研究人員一直追蹤，發現了它們在大腦中對應的靶細胞。研究人員發現這些資訊的主要接收者是一小群大腦神經元細胞，它們是控制活動和睡眠規律的大腦神經網路的一部分。當溫度提示迴路被啟用時，通常可以被晨光啟用的這些靶細胞就會休息。
“Temperature sensing is one of the most fundamental sensory modalities,” said Gallio, whose group is one of only a few in the world that is systematically studying temperature sensing in fruit flies. “The principles we are finding in the fly brain -- the logic and organization -- may be the same all the way to humans. Whether fly or human, the sensory systems have to solve the same problems, so they often do it in the same ways.”
加里奧的研究團隊是世界上為數不多的系統研究果蠅溫度感應的團隊之一，他表示：“溫度感應是最基本的感覺方式之一。我們在果蠅大腦中發現的原理——邏輯和組織結構——可能對人類來說都是一樣的。無論蒼蠅還是人類，感覺系統都必須處理同樣的問題，因此它們的處理機制通常也是相似的。”
來源：Study Finds，news.northwestern.edu編輯：董靜
來源：中國日報網
