Tanaka Hiroki, Ohzawa Izumi
Graduate School of Frontier Biosciences and School of Engineering Science, Osaka University, Osaka, Japan.
J Neurophysiol. 2009 Mar;101(3):1444-62. doi: 10.1152/jn.90749.2008. Epub 2008 Dec 24.
Neurons with surround suppression have been implicated in processing high-order visual features such as contrast- or texture-defined boundaries and subjective contours. However, little is known regarding how these neurons encode high-order visual information in a systematic manner as a population. To address this issue, we have measured detailed spatial structures of classical center and suppressive surround regions of receptive fields of primary visual cortex (V1) neurons and examined how a population of such neurons allow encoding of various high-order features and shapes in visual scenes. Using a novel method to reconstruct structures, we found that the center and surround regions are often both elongated parallel to each other, reminiscent of on and off subregions of simple cells without surround suppression. These structures allow V1 neurons to extract high-order contours of various orientations and spatial frequencies, with a variety of optimal values across neurons. The results show that a wide range of orientations and widths of the high-order features are systematically represented by the population of V1 neurons with surround suppression.
具有周边抑制的神经元已被认为参与处理高阶视觉特征，如对比度或纹理定义的边界以及主观轮廓。然而，对于这些神经元如何作为一个群体以系统的方式编码高阶视觉信息，我们知之甚少。为了解决这个问题，我们测量了初级视觉皮层（V1）神经元感受野的经典中心和抑制性周边区域的详细空间结构，并研究了这样一群神经元如何在视觉场景中对各种高阶特征和形状进行编码。使用一种新颖的方法来重建结构，我们发现中心和周边区域通常彼此平行拉长，这让人联想到没有周边抑制的简单细胞的开和关子区域。这些结构使V1神经元能够提取各种方向和空间频率的高阶轮廓，并且不同神经元具有各种最优值。结果表明，具有周边抑制的V1神经元群体系统地表示了高阶特征的广泛方向和宽度。
