生物谷：你不是唯一對(duì)專業(yè)雜技表演者的手眼高度協(xié)調(diào)能力感到驚訝的人,。長(zhǎng)期以來(lái),，大腦如何通過(guò)視網(wǎng)膜平面圖像產(chǎn)生物體三維空間結(jié)構(gòu)和位置的認(rèn)識(shí)，一直困擾著神經(jīng)學(xué)家,。不過(guò),，美國(guó)科學(xué)家的一項(xiàng)最新研究打破了這一狀況，他們確定了大腦與三維視覺(jué)處理相關(guān)的區(qū)域,。相關(guān)論文發(fā)表在8月2日的《神經(jīng)元》雜志上,。
靈長(zhǎng)類動(dòng)物獲得深度直覺(jué)和三維結(jié)構(gòu)認(rèn)識(shí)需要兩個(gè)主要的視覺(jué)線索：雙眼視差（spatial binocular disparity）和物體運(yùn)動(dòng)時(shí)感知到的外形變化。不過(guò),，大腦如何整合這兩方面的信息一直是個(gè)謎團(tuán),。
最近，通過(guò)兩項(xiàng)獨(dú)立的實(shí)驗(yàn)研究,，比利時(shí)魯汶天主教大學(xué)（Catholic University of Leuven）的神經(jīng)學(xué)家Guy Orban和同事發(fā)現(xiàn),，一個(gè)名為頂葉內(nèi)前部區(qū)（anterior intraparietal cortex，簡(jiǎn)稱AIP）的大腦區(qū)域與上述兩種視覺(jué)線索都緊密相關(guān),。
在第一項(xiàng)實(shí)驗(yàn)中,，研究人員讓猴子用觀看連接線段的旋轉(zhuǎn)圖像，但每次只能用一只眼睛,。而另一項(xiàng)實(shí)驗(yàn)中,，猴子可以用雙眼觀看計(jì)算機(jī)模擬的復(fù)雜物體，從而能夠通過(guò)雙眼視差來(lái)感知深度結(jié)構(gòu),。通過(guò)功能核磁共振成像（fMRI）,，研究人員確定了集中處理兩種信息的大腦AIP區(qū)域。
此前,，科學(xué)家認(rèn)為AIP區(qū)域與靈長(zhǎng)動(dòng)物手的運(yùn)動(dòng)緊密相關(guān),，比如撿起一支筆。這種大腦引導(dǎo)手進(jìn)行“夠和抓”動(dòng)作是靈長(zhǎng)類動(dòng)物所特有的,，因此Orban相信,，大腦AIP區(qū)域是在靈長(zhǎng)動(dòng)物與其他動(dòng)物分道揚(yáng)鑣后才進(jìn)化產(chǎn)生的。
英國(guó)牛津大學(xué)專門研究雙眼知覺(jué)的神經(jīng)學(xué)家Andrew Parker認(rèn)為該項(xiàng)研究具有重要而廣泛的意義,。他說(shuō),，“該研究結(jié)論很大程度上拓展了我們對(duì)AIP介入過(guò)程的認(rèn)識(shí)。如果猴子可以自由移動(dòng)這一因素不影響實(shí)驗(yàn)結(jié)論的話,，我對(duì)深度知覺(jué)的看法將發(fā)生改變,。”（科學(xué)網(wǎng) 任霄鵬/編譯）
原始出處:
Neuron, Vol 55, 493-505, 02 August 2007
Article
Anterior Regions of Monkey Parietal Cortex Process Visual 3D Shape
Jean-Baptiste Durand,1,5 Koen Nelissen,1,5 Olivier Joly,1,5 Claire Wardak,1 James T. Todd,2 J. Farley Norman,3 Peter Janssen,1 Wim Vanduffel,1,4 and Guy A. Orban1,
1 Lab Neuro- en Psychofysiologie, K.U. Leuven, Medical School, Campus Gasthuisberg, Herestraat 49, B-3000, Leuven, Belgium
2 Department of Psychology, Ohio State University, 142 Townshend Hall, Columbus, OH 43210, USA
3 Department of Psychology, Western Kentucky University, 1906 College Heights Boulevard, Bowling Green, KY 42101-1030, USA
4 Athinoula A. Martinos Center for Biomedical Imaging, 13th Street, Charlestown, MA 02129, USA
Corresponding author
Guy A. Orban
[email protected]
The intraparietal cortex is involved in the control of visually guided actions, like reach-to-grasp movements, which require extracting the 3D shape and position of objects from 2D retinal images. Using fMRI in behaving monkeys, we investigated the role of the intraparietal cortex in processing stereoscopic information for recovering the depth structure and the position in depth of objects. We found that while several areas (CIP, LIP, and AIP on the lateral bank; PIP and MIP on the medial bank) are activated by stereoscopic stimuli, AIP and an adjoining portion of LIP are sensitive only to depth structure. Furthermore, only these two regions are sensitive to both the depth structure and the 2D shape of small objects. These results indicate that extracting 3D spatial information from stereo involves several intraparietal areas, among which AIP and anterior LIP are more specifically engaged in extracting the 3D shape of objects.
