蠅腦只有不到六分之一立方毫米，但蒼蠅在飛行時(shí)卻能大量且精確地處理眼睛接受的信息,，其性能勝過(guò)超級(jí)電腦,。為進(jìn)一步解開(kāi)蠅腦之謎，德國(guó)科學(xué)家成功研發(fā)了一種能夠捕捉蠅腦神經(jīng)細(xì)胞活動(dòng)的研究方法,。
德國(guó)馬克斯·普朗克神經(jīng)生物學(xué)研究所12日發(fā)表公報(bào)說(shuō),，該所研究人員以果蠅為實(shí)驗(yàn)對(duì)象，用發(fā)光二極管顯示屏上運(yùn)動(dòng)的條狀圖案刺激其視覺(jué),，并應(yīng)用肌鈣蛋白為基礎(chǔ)的熒光標(biāo)記分子TN－XXL來(lái)標(biāo)記某個(gè)特定的神經(jīng)細(xì)胞,。他們還應(yīng)用雙光子激光顯微鏡，將其頻率調(diào)到與顯示屏相同的頻率,，以區(qū)分熒光標(biāo)記分子和顯示屏的光線,。
研究人員說(shuō)，這是學(xué)界首次成功研發(fā)出深入研究蠅腦神經(jīng)細(xì)胞活動(dòng)機(jī)制的方法，下一步將逐一研究蠅腦的約10萬(wàn)個(gè)神經(jīng)細(xì)胞,。
該研究成果最新發(fā)表在英國(guó)《自然－神經(jīng)科學(xué)》網(wǎng)絡(luò)版上,。(生物谷Bioon.net)
生物谷推薦原文出處：
Nature Neuroscience doi:10.1038/nn.2595
Visualizing retinotopic half-wave rectified input to the motion detection circuitry of Drosophila
Dierk F Reiff,Johannes Plett,Marco Mank,Oliver Griesbeck& Alexander Borst
In the visual system of Drosophila, photoreceptors R1–R6 relay achromatic brightness information to five parallel pathways. Two of them, the lamina monopolar cells L1 and L2, represent the major input lines to the motion detection circuitry. We devised a new method for optical recording of visually evoked changes in intracellular Ca2+ in neurons using targeted expression of a genetically encoded Ca2+ indicator. Ca2+ in single terminals of L2 neurons in the medulla carried no information about the direction of motion. However, we found that brightness decrements (light-OFF) induced a strong increase in intracellular Ca2+ but brightness increments (light-ON) induced only small changes, suggesting that half-wave rectification of the input signal occurs. Thus, L2 predominantly transmits brightness decrements to downstream circuits that then compute the direction of image motion.
