《神經(jīng)科學(xué)雜志》(The Journal of Neuroscience, 29(2), 460-465) 于2009年1月14日，刊登了北京大學(xué)心理學(xué)系和機(jī)器感知與智能教育部重點(diǎn)實(shí)驗(yàn)室方方研究員的最新研究成果——人類早期視皮層對(duì)邊緣所有權(quán)的選擇性以及注意的調(diào)節(jié)作用（Border ownership selectivity in human early visual cortex and its modulation by attention）。在這項(xiàng)研究中,，方方研究員利用功能性核磁共振適應(yīng)（fMRI adaptation）技術(shù)克服了fMRI空間分辨率相對(duì)較低的缺陷，首次揭示了人類次級(jí)視皮層(V2)可以對(duì)邊緣所有權(quán)進(jìn)行編碼，以及視覺(jué)注意在這種編碼過(guò)程中所起到的關(guān)鍵作用。
視覺(jué)科學(xué)的核心問(wèn)題是視覺(jué)神經(jīng)系統(tǒng)如何利用雙眼接受到的二維信息構(gòu)建立體的三維世界,，并識(shí)別三維世界中的物體。視皮層對(duì)視覺(jué)信息加工的第一步是邊緣提取,，這主要由初級(jí)視皮層(V1)來(lái)完成,。隨后則是確定邊緣屬于視覺(jué)場(chǎng)景中的哪一個(gè)物體，即邊緣所有權(quán),。在此基礎(chǔ)上,，視覺(jué)系統(tǒng)才能將分屬不同物體的邊緣連接起來(lái)，從而形成物體知覺(jué)。在過(guò)去二十多年中,，對(duì)邊緣所有權(quán)神經(jīng)表征的研究一直是視覺(jué)科學(xué)中的熱點(diǎn)問(wèn)題,。但靈長(zhǎng)類的電生理研究（Nature Neuroscience, 2007）和人類功能性核磁共振研究（Science，2001）并不一致,，前者發(fā)現(xiàn)這種神經(jīng)表征位于早期視皮層,，而后者則發(fā)現(xiàn)該表征位于高級(jí)視皮層。方方博士的研究利用功能性核磁共振適應(yīng)技術(shù),，靈敏地探測(cè)出人類早期視皮層可以表征邊緣所有權(quán),，并將這種表征傳遞到高級(jí)視皮層，從而融合解釋了以前的學(xué)術(shù)爭(zhēng)論,。關(guān)于邊緣所有權(quán)神經(jīng)表征的探索同時(shí)對(duì)機(jī)器感知研究也有重要意義,，該研究為復(fù)雜場(chǎng)景中的物體識(shí)別算法，提供了來(lái)自神經(jīng)科學(xué)的新的理論依據(jù),。
《神經(jīng)科學(xué)雜志》由美國(guó)神經(jīng)科學(xué)學(xué)會(huì)主辦,，是神經(jīng)科學(xué)領(lǐng)域的權(quán)威主流期刊。這項(xiàng)研究受到北京大學(xué)985“百人計(jì)劃”項(xiàng)目和國(guó)家自然科學(xué)基金委的支持,。（生物谷Bioon.com）
生物谷推薦原始出處：
The Journal of Neuroscience,，doi:10.1523/JNEUROSCI.4628-08.2009，F(xiàn)ang Fang,，Daniel Kersten
Border Ownership Selectivity in Human Early Visual Cortex and its Modulation by Attention
Fang Fang,1 Huseyin Boyaci,2 and Daniel Kersten3
1Department of Psychology and Key Laboratory of Machine Perception (Ministry of Education), Peking University, Beijing 100871, China, 2Department of Psychology, Bilkent University, Ankara 06800, Turkey, and 3Department of Psychology, University of Minnesota, Minneapolis, Minnesota 55455
Natural images are usually cluttered because objects occlude one another. A critical aspect of recognizing these visual objects is to identify the borders between image regions that belong to different objects. However, the neural coding of border ownership in human visual cortex is largely unknown. In this study, we designed two simple but compelling stimuli in which a slight change of contextual information could induce a dramatic change of border ownership. Using functional MRI adaptation, we found that border ownership selectivity in V2 was robust and reliable across subjects, and it was largely dependent on attention. Our study provides the first human evidence that V2 is a critical area for the processing of border ownership and that this processing depends on the modulation from higher-level cortical areas.
