在演講過程中，人們會自然而然地在合適的地方加以停頓,，以取得更好的演講效果,。日本科學家發(fā)現(xiàn),，之所以有這樣無意識的短暫停頓，是因為大腦的神經(jīng)細胞能夠像沙漏一樣計算時間,。
據(jù)共同社報道,，玉川大學教授丹治順等人以日本獼猴為研究對象，訓練獼猴分別在黃燈亮2秒鐘,、紅燈亮4秒鐘或綠燈亮8秒鐘后操作控制桿,，并同時監(jiān)控從燈亮到操作控制桿這段時間內(nèi)，獼猴大腦額葉輔助運動區(qū)中每一個神經(jīng)細胞的活動情況,。
經(jīng)過以不斷變化顏色和時間的組合方式多次實驗,，研究人員發(fā)現(xiàn)，獼猴大腦額葉輔助運動區(qū)有3種神經(jīng)細胞與2秒的間隔控制相關：第一種是判別細胞,，這種細胞無論何種顏色和時間組合都是針對表示2秒的顏色作出反應,；第二種是像沙漏一樣計算時間的細胞，這種細胞的電信號強度以2秒為間隔發(fā)生變化,；第三種細胞在規(guī)定時間過去后,，促使肢體發(fā)出操作控制桿的動作。對4秒或8秒時間間隔,，大腦也有類似的3種神經(jīng)細胞存在,。
研究人員說，實驗表明,，大腦是根據(jù)電信號的變化來描述時間這樣的抽象概念,。如果經(jīng)常練習演講的停頓方法，那么久而久之神經(jīng)細胞就能幫助你“熟能生巧地”在該停頓的地方停頓,。
這一成果已登載在最新一期英國《自然·神經(jīng)科學》雜志網(wǎng)絡版上,。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature Neuroscience 1 March 2009 | doi:10.1038/nn.2272
Interval time coding by neurons in the presupplementary and supplementary motor areas
Akihisa Mita1, Hajime Mushiake1, Keisetsu Shima1, Yoshiya Matsuzaka1 & Jun Tanji1,2
Abstract
Interval timing is an essential guiding force of behavior. Previous reports have implicated the prefrontal and parietal cortex as being involved in time perception and in temporal decision making. We found that neurons in the medial motor areas, in particular the presupplementary motor area, participate in interval timing in the range of seconds. Monkeys were trained to perform an interval-generation task that required them to determine waiting periods of three different durations. Neuronal activity contributed to the process of retrieving time instructions from visual cues, signaled the initiation of action in a time-selective manner, and developed activity to represent the passage of time. These results specify how medial motor areas take part in initiating actions on the basis of self-generated time estimates.
1 Department of Physiology, Tohoku University School of Medicine, Sendai, Japan.
2 Brain Research Institute, Tamagawa University, Machida, Tokyo, Japan.
