Equiluminance cells in visual cortical area v4.
Equiluminance cells in visual cortical area v4.
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DOI：
10.1523/jneurosci.1890-11.2011
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发表时间：
2011-08-31
期刊：
影响因子：
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通讯作者：
Pasupathy A
中科院分区：
文献类型：
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作者：
Bushnell BN;Harding PJ;Kosai Y;Bair W;Pasupathy A
我们报道了猕猴的一类新的V4神经元，选择性地响应等光的彩色形式。这些“等亮度”细胞之所以与众不同，是因为它们违背了整个视觉系统的既定趋势，即在低亮度对比度下反应最小，并随着对比度的增加而增长和饱和。均衡亮度细胞约占V4的22%，表现出相反的行为：响应在接近零对比度时最大，并随着对比度的增加而降低。虽然均衡细胞优先响应等亮度的彩色刺激，但强烈的色调调节并不是它们的显著特征——一些均衡细胞确实表现出强烈的单峰色调调节，但许多细胞对色调调节很少或没有。我们发现，与具有更传统对比度响应功能的其他类别的V4细胞相比，等亮度细胞具有颜色和形状选择性。那些更传统的细胞对消色差亮度和等色刺激的反应同样好，类似于V1中描述的彩色-亮度细胞。等亮度细胞的存在，在V1和V2中未被报道，表明在V4中具有色度定义的边界和形状被赋予特殊地位，并提出了在V4中等亮度形成和高对比度形成在单独通道中处理的可能性。
We report a novel class of V4 neuron in the macaque monkey that responds selectively to equiluminant colored form. These "equiluminance" cells stand apart because they violate the well established trend throughout the visual system that responses are minimal at low luminance contrast and grow and saturate as contrast increases. Equiluminance cells, which compose about 22% of V4, exhibit the opposite behavior: responses are greatest near zero contrast and decrease as contrast increases. While equilumiance cells respond preferentially to equiluminant colored stimuli, strong hue tuning is not their distinguishing feature—some equilumiance cells do exhibit strong unimodal hue tuning but many show little or no tuning for hue. We find that equiluminance cells are color and shape selective to a degree comparable to other classes of V4 cells with more conventional contrast response functions. Those more conventional cells respond equally well to achromatic luminance and equiluminant color stimuli, analogous to color-luminance cells described in V1. The existence of equiluminance cells, which have not been reported in V1 or V2, suggests that chromatically-defined boundaries and shapes are given special status in V4 and raises the possibility that form at equiluminance and form at higher contrasts are processed in separate channels in V4.