J Neurosci：王伟等发现猕猴V4视区对真实和错觉轮廓方位感知不变性的加工处理

5月16日，《神经科学杂志》Journal of Neuroscience在线发表了题为“Equivalent representation of real and illusory contours in macaque V4”的研究论文。这项工作主要由上海生科院神经所研究生潘炎夏和导师王伟研究员及其合作者共同完成的。

研究错觉轮廓（illusory contours）在大脑视皮层中的神经感知和处理机制，是人们了解视知觉脑机制的一个重要研究领域。前人的研究表明在猕猴初级视皮层V1区和次级视皮层V2区已有部分神经元对错觉轮廓视觉刺激有明显反应，后续的人类脑功能成像研究则提示高级视区在错觉轮廓和图形的处理中有重要作用，因而，大脑对错觉轮廓和错觉图形的处理可能是一个涉及腹侧视觉通路多级脑区的复杂整合过程。

然而，在群体和单个神经元水平上，腹侧视觉通路中哪个视区是对错觉轮廓和真实轮廓进行方位感知不变性表征的最早视区，这一基本科学问题仍不清楚。研究者通过对猕猴V1，V2和V4多脑区同时记录并加以清醒猴V4电生理单细胞记录，直接对比研究了不同视区对真实轮廓与错觉轮廓朝向反应的感知不变性。研究者发现在猕猴视皮层V4区具有同样朝向的方位功能组织以相同的方式既处理真实轮廓也处理错觉轮廓信息。

而在V1及V2视区同样的错觉轮廓刺激所激活的皮层功能组织的朝向选择性与所用来构成错觉轮廓的诱导短线（inducers）有关。这些结果不仅表明V4是一个在错觉轮廓方位不变性感知中起重要作用的脑区，而且进一步对整体轮廓在V4视区是如何由各个构成组分通过多脑区整合形成的可能神经机制（contour integration），这一视觉科学的中心问题，给与了启示。

这项工作得到了科技部973计划和中国科学院“百人计划”资助。（生物谷Bioon.com）

doi:10.1523/​JNEUROSCI.6140-11.2012
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Equivalent Representation of Real and Illusory Contours in Macaque V4

Yanxia Pan1, Minggui Chen2, Jiapeng Yin1, Xu An1, Xian Zhang1, Yiliang Lu1, Hongliang Gong1, Wu Li2, and Wei Wang1

The cortical processing of illusory contours provides a unique window for exploring the brain mechanisms underlying visual perception. Previous electrophysiological single-cell recordings demonstrate that a subgroup of cells in macaque V1 and V2 signal the presence of illusory contours, whereas recent human brain imaging studies reveal higher-order visual cortices playing a central role in illusory figure processing. It seems that the processing of illusory contours/figures may engage multiple cortical interactions between hierarchically organized processing stages in the ventral visual pathway of primates. However, it is not yet known in which brain areas illusory contours are represented in the same manner as real contours at both the population and single-cell levels. Here, by combining intrinsic optical imaging in anesthetized rhesus macaques with single-cell recordings in awake ones, we found a complete overlap of orientation domains in visual cortical area V4 for processing real and illusory contours. In contrast, the orientation domains mapped in early visual areas V1 and V2 mainly encoded the local physical stimulus features inducing the subjective perception of global illusory contours. Our results indicate that real and illusory contours are encoded equivalently by the same functional domains in V4, suggesting that V4 is a key cortical locus for integration of local features into global contours.