進(jìn)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，“被窩里面好暖好舒服，哪里都不想伸出來。”

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(xué)角度詳細(xì)說說，為什么冬天起床更困難。

A study conducted by neurobiologists from Northwestern University made it possible to elucidate the mechanisms underlying this phenomenon.
美國西北大學(xué)神經(jīng)生物學(xué)家進(jìn)行的一項(xiàng)研究或許能解釋導(dǎo)致這種現(xiàn)象的機(jī)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(fā)現(xiàn)了一個溫度提示回路，可以將低溫信息從觸角傳輸?shù)酱竽X。

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，通過該回路，季節(jié)性寒冷和黑暗環(huán)境可以抑制果蠅大腦中促進(jìn)活動和清醒的神經(jīng)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(xué)院神經(jīng)生物學(xué)副教授馬可·加利奧表示：“這有助于解釋為什么無論對蒼蠅還是人類來說，在冬天的早上醒來都很困難。通過研究果蠅的行為，我們可以更好地理解溫度對調(diào)節(jié)睡眠的重要性?！?br>

The study, led by Gallio and conducted in Drosophila melanogaster, was published in the journal Current Biology.
這項(xiàng)研究由加利奧主導(dǎo)，研究對象為黑腹果蠅，研究成果發(fā)表在《當(dāng)代生物學(xué)》雜志上。

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(jīng)元，它們只對低于果蠅溫度舒適區(qū)的氣溫作出反應(yīng)。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(jīng)元后，研究人員一直追蹤，發(fā)現(xiàn)了它們在大腦中對應(yīng)的靶細(xì)胞。研究人員發(fā)現(xiàn)這些信息的主要接收者是一小群大腦神經(jīng)元細(xì)胞，它們是控制活動和睡眠規(guī)律的大腦神經(jīng)網(wǎng)絡(luò)的一部分。當(dāng)溫度提示回路被激活時，通常可以被晨光激活的這些靶細(xì)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(tuán)隊(duì)是世界上為數(shù)不多的系統(tǒng)研究果蠅溫度感應(yīng)的團(tuán)隊(duì)之一，他表示：“溫度感應(yīng)是最基本的感覺方式之一。我們在果蠅大腦中發(fā)現(xiàn)的原理——邏輯和組織結(jié)構(gòu)——可能對人類來說都是一樣的。無論蒼蠅還是人類，感覺系統(tǒng)都必須處理同樣的問題，因此它們的處理機(jī)制通常也是相似的?！?/p>

來源：Study Finds，news.northwestern.edu
編輯：董靜