Riemslag F C, Ringo J L, Spekreijse H, Verduyn Lunel H F
J Physiol. 1985 Jun;363:191-209. doi: 10.1113/jphysiol.1985.sp015704.
Electroretinograms (e.r.g.s) and visually evoked potentials (v.e.p.s) to pattern stimuli were recorded simultaneously from healthy subjects. The stimuli were produced by a configuration in which the luminance of two sets of spatial elements (checks) could be modulated independently. Experiments were designed to distinguish between contrast responses and non-linear luminance responses. In the first of two basic experiments, the luminance of only one set of checks was modulated, at a constant level in every trial. The other set was not modulated, but its luminance was set at various levels. Under these conditions the local luminance stimulation was kept equal for every trial whereas the contrast stimulation varied. Therefore, local luminance responses in these experiments were expected to be constant and contrast responses were expected to vary. The e.r.g.s were identical for all luminance settings of the unmodulated checks, suggesting that luminance rather than contrast determines the response. The v.e.p.s showed, on the contrary, the behaviour expected for contrast responses. In the second basic experiment the local luminance stimulation was also kept constant, but the phase difference between the modulations of the two sets of checks was varied between 0 deg (pure luminance stimulation) and 180 deg (pattern reversal). In this type of experiment the second harmonic responses to local luminance modulation are expected to decrease to a minimum as phase difference goes from 0 to 90 deg and increase again as phase difference goes to 180 deg. Contrast responses are expected to increase monotonically from zero to maximal at phase difference shifts from 0 deg (no contrast stimulation) to 180 deg (contrast reversal). The e.r.g.s decreased to a minimum at 90 deg phase difference and increase again with phase difference going to 180 deg. At 0 and 180 deg the same value was recorded. Consequently, the e.r.g. behaviour suggests a luminance origin of the responses. The v.e.p.s monotonically increased as phase difference went from 0 to 180 deg, thus suggesting a contrast origin of the responses. Two additional control experiments were performed. The first experiment compared the responses to homogeneous field red/green exchange and pattern red/green exchange, with the luminances of the red and green sources matched by heterochromatic flicker photometry. The exchange of luminance-matched red and green checks (pattern reversal) did not produce different e.r.g. responses from those recorded in response to homogeneous field red/green exchange. The v.e.p. showed a significant increase for the pattern stimulus.(ABSTRACT TRUNCATED AT 400 WORDS)
从健康受试者身上同时记录了视网膜电图（e.r.g.s）和对图形刺激的视觉诱发电位（v.e.p.s）。刺激由一种配置产生，其中两组空间元素（方格）的亮度可以独立调制。实验旨在区分对比度响应和非线性亮度响应。在两个基本实验中的第一个实验中，每次试验中仅一组方格的亮度以恒定水平调制。另一组未调制，但其亮度设置为不同水平。在这些条件下，每次试验的局部亮度刺激保持相等，而对比度刺激则有所变化。因此，预计这些实验中的局部亮度响应是恒定的，而对比度响应会有所不同。对于未调制方格的所有亮度设置，视网膜电图都是相同的，这表明是亮度而非对比度决定了响应。相反，视觉诱发电位表现出对比度响应所预期的行为。在第二个基本实验中，局部亮度刺激也保持恒定，但两组方格调制之间的相位差在0度（纯亮度刺激）和180度（图形反转）之间变化。在这种类型的实验中，随着相位差从0度到90度，对局部亮度调制的二次谐波响应预计会降至最低，而随着相位差达到180度又会再次增加。随着相位差从0度（无对比度刺激）到180度（对比度反转）的变化，对比度响应预计会从零单调增加到最大值。视网膜电图在90度相位差时降至最低，并随着相位差达到180度再次增加。在0度和180度时记录到相同的值。因此，视网膜电图的行为表明响应起源于亮度。随着相位差从0度到180度，视觉诱发电位单调增加，从而表明响应起源于对比度。还进行了另外两个对照实验。第一个实验比较了对均匀场红/绿交换和图形红/绿交换的响应，通过异色闪烁光度法使红、绿光源的亮度匹配。亮度匹配的红、绿方格的交换（图形反转）所产生的视网膜电图响应与对均匀场红/绿交换记录的响应没有差异。对于图形刺激，视觉诱发电位显示出显著增加。（摘要截断于400字）
