Mullen Kathy T, Sakurai Masato, Chu William
McGill Vision Research, Department of Ophthalmology, McGill University, 687 Pine Avenue West, H4-14, Montréal, Québec H3A 1A1, Canada.
Perception. 2005;34(8):951-9. doi: 10.1068/p5374.
We have assessed the optimal cone contrast sensitivity across eccentricity in human vision of the two cone-opponent mechanisms [L/M or red-green, and S/(L + M) or blue-yellow] and the luminance mechanism. We have used a novel stimulus, termed a 'sinring', that is a radially modulated sine-wave arc, Gaussian enveloped in both angular and radial directions. This stimulus overcomes the problem inherent in Gabor stimuli of confounding stimulus spatial frequency, size, and eccentricity and so allows contrast sensitivity to be tracked accurately into the periphery. Our results show that L/M cone opponency declines steeply across the human periphery and becomes behaviourally absent by 25-30 deg (in the nasal field). This result suggests that any L/M cone-opponent neurons found in primate peripheral retina beyond this limit are unlikely to be significant for colour contrast detection measured behaviourally.
我们评估了在人类视觉中，两种颜色拮抗机制[L/M或红-绿，以及S/(L + M)或蓝-黄]和亮度机制在不同离心率下的最佳视锥细胞对比敏感度。我们使用了一种新型刺激，称为“sinring”，它是一个径向调制的正弦波弧，在角度和径向方向上均为高斯包络。这种刺激克服了Gabor刺激中固有的混淆刺激空间频率、大小和离心率的问题，因此能够准确地追踪周边区域的对比敏感度。我们的结果表明，L/M视锥细胞拮抗在人类周边区域急剧下降，在25 - 30度（在鼻侧视野）时在行为上消失。这一结果表明，在灵长类动物周边视网膜中超过此限度发现的任何L/M视锥细胞拮抗神经元，对于行为测量的颜色对比检测不太可能具有重要意义。
