Rabin J, Switkes E, Crognale M, Schneck M E, Adams A J
School of Optometry, University of California Berkeley 94720.
Vision Res. 1994 Oct;34(20):2657-71. doi: 10.1016/0042-6989(94)90222-4.
Visual evoked potentials (VEPs) were measured for sinusoidal gratings with spatio-chromatic modulation defined in a three-dimensional color space. The spatio-chromatic modulation of the gratings can be decomposed into contributions from an achromatic luminance varying component, an isoluminant component which modulates only the activities of L cones and M cones, and an isoluminant component corresponding to modulation of only S-cone activity. The emphasis of this report is the nature of VEPs resulting from isoluminant spatio-chromatic modulation. The VEP response was characterized along a number of spatial, temporal, and chromatic stimulus dimensions: contrast, spatial frequency, chromaticity in the isoluminant plane, chrominance/luminance ratio, orientation, and temporal frequency. Isoluminant VEPs resulting from stimuli modulating L and M cones are compared with those from S-cone modulation. When appropriate spatiotemporal conditions are employed, both types produce robust VEPs; however, the S-pathway VEPs show considerably longer latencies than do those from LM-pathway activation. The VEP results are compared to psychophysical and single unit electrophysiological observations. VEP latencies exhibit the lowpass character of psychophysical chromatic contrast sensitivity functions but VEP amplitudes show bandpass tuning along both the S and LM axes. An oblique effect, i.e. shorter latencies for horizontal and vertical gratings than for diagonal, is observed in the isoluminant VEP. S-pathway VEPs are used to demonstrate an electophysiological correlate of transient tritanopia. Normative amplitude and latency data for VEPs from selectivity stimulated chromatic mechanisms provide a baseline for clinical electrodiagnostic applications.
针对在三维颜色空间中定义的具有时空色度调制的正弦光栅，测量了视觉诱发电位（VEP）。光栅的时空色度调制可分解为来自无彩色亮度变化分量、仅调制L锥和M锥活动的等亮度分量以及仅对应于S锥活动调制的等亮度分量的贡献。本报告的重点是由等亮度时空色度调制产生的VEP的性质。VEP反应是沿着多个空间、时间和色度刺激维度进行表征的：对比度、空间频率、等亮度平面中的色度、色度/亮度比、方向和时间频率。将调制L锥和M锥的刺激产生的等亮度VEP与S锥调制产生的等亮度VEP进行比较。当采用适当的时空条件时，两种类型都会产生强烈的VEP；然而，S通路VEP的潜伏期比LM通路激活产生的VEP潜伏期长得多。将VEP结果与心理物理学和单单元电生理观察结果进行比较。VEP潜伏期表现出心理物理学色度对比敏感度函数的低通特性，但VEP振幅在S轴和LM轴上均显示带通调谐。在等亮度VEP中观察到倾斜效应，即水平和垂直光栅的潜伏期比对角光栅的潜伏期短。S通路VEP用于证明瞬态蓝色盲的电生理相关性。来自选择性刺激色度机制的VEP的规范振幅和潜伏期数据为临床电诊断应用提供了基线。
