Regan D, Regan M P
Department of Ophthalmology, Dalhousie University, Halifax, Nova Scotia, Canada.
Vision Res. 1988;28(1):187-91.
Electrophysiological responses in human index an interaction between responses to two gratings that is relatively independent of the distribution of light in the retinal image. Two 5 cycle/deg sinewave gratings were superimposed, one counterphase-modulated at F1 Hz and the other at F2 Hz. Nonlinear interaction terms of frequency (nF1 +/- mF2) were recorded that could not be produced by superimposing the F1 Hz grating on blank-field 7 Hz flicker. A local luminance origin could be excluded for the (2F1 + 2F2) term and for the suppression of 2F1 and 4F1, but not for the (F1 + F2), (F1 + 3F2) and (5F2 - F1) terms. The relative spatial phase of the two gratings was varied, thus altering the light distribution in the retinal image without changing its spatial power spectrum. The (2F1 + 2F2) Hz contrast-specific grating-grating interaction term was almost unaffected by these substantial changes in retinal image light distribution providing that the spatial frequency power spectrum of the retinal image was held constant. The (2F1 + 2F2) term and the suppression of 2F1 were both tuned to spatial frequency.
人类食指的电生理反应显示，对两个光栅的反应之间存在一种相互作用，这种相互作用相对独立于视网膜图像中的光分布。叠加了两个5周期/度的正弦波光栅，一个以F1赫兹进行反相调制，另一个以F2赫兹进行反相调制。记录到了频率的非线性相互作用项（nF1 +/- mF2），这些项无法通过将F1赫兹的光栅叠加在7赫兹的空白场闪烁上产生。对于（2F1 + 2F2）项以及对2F1和4F1的抑制，可以排除局部亮度起源，但对于（F1 + F2）、（F1 + 3F2）和（5F2 - F1）项则不能排除。改变了两个光栅的相对空间相位，从而在不改变视网膜图像空间功率谱的情况下改变了视网膜图像中的光分布。只要视网膜图像的空间频率功率谱保持不变，（2F1 + 2F2）赫兹的对比度特异性光栅 - 光栅相互作用项几乎不受视网膜图像光分布这些显著变化的影响。（2F1 + 2F2）项和对2F1的抑制都对空间频率进行了调谐。
