生物谷：你不是唯一對專業(yè)雜技表演者的手眼高度協(xié)調(diào)能力感到驚訝的人,。長期以來，大腦如何通過視網(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,，一直困擾著神經(jīng)學(xué)家。不過,，美國科學(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,。
靈長類動物獲得深度直覺和三維結(jié)構(gòu)認(rèn)識需要兩個主要的視覺線索：雙眼視差（spatial binocular disparity）和物體運(yùn)動時感知到的外形變化。不過,，大腦如何整合這兩方面的信息一直是個謎團(tuán),。
最近，通過兩項(xiàng)獨(dú)立的實(shí)驗(yàn)研究,，比利時魯汶天主教大學(xué)（Catholic University of Leuven）的神經(jīng)學(xué)家Guy Orban和同事發(fā)現(xiàn),，一個名為頂葉內(nèi)前部區(qū)（anterior intraparietal cortex，簡稱AIP）的大腦區(qū)域與上述兩種視覺線索都緊密相關(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算機(jī)模擬的復(fù)雜物體，從而能夠通過雙眼視差來感知深度結(jié)構(gòu),。通過功能核磁共振成像（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)域與靈長動物手的運(yùn)動緊密相關(guān),，比如撿起一支筆。這種大腦引導(dǎo)手進(jìn)行“夠和抓”動作是靈長類動物所特有的,，因此Orban相信,，大腦AIP區(qū)域是在靈長動物與其他動物分道揚(yáng)鑣后才進(jìn)化產(chǎn)生的。
英國牛津大學(xué)專門研究雙眼知覺的神經(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,，“該研究結(jié)論很大程度上拓展了我們對AIP介入過程的認(rèn)識。如果猴子可以自由移動這一因素不影響實(shí)驗(yàn)結(jié)論的話,，我對深度知覺的看法將發(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.
