Cone contrast influence on components of the pattern onset/offset VECP
Cone contrast influence on components of the pattern onset/offset VECP
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DOI：
10.1111/j.1475-1313.2010.00751.x
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发表时间：
2010-09-01
影响因子：
2.9
通讯作者：
Silveira, L. C. L.
中科院分区：
文献类型：
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作者：
Gomes, B. D.;Souza, G. S.;Silveira, L. C. L.
从健康的正常三色视者（n = 12）的头皮记录瞬时视觉皮层诱发电位（VECP）。vecp是由两种模式刺激的开始/偏移呈现引起的：等色亮度调制和等光红绿调制正弦波光栅。测量了起始/偏移VECP的主要起始分量的振幅和延迟，并将其绘制为池锥对比度的对数函数。消色差分量C1和色差分量N1随对数对比度线性增加，但N1的对比度增益高于C1。迟发成分，消色差C2和色差N2，具有相似的对比度增益，并且作为对比度水平的函数具有相似的响应：两者都在低到中对比度范围内增加，并在高对比度水平下饱和。在池锥对比测试的范围内，C1和N1表现出相似的延迟，而C2表现出比N2短的延迟。我们认为C1和N1是由相同的视觉机制产生的，具有高红绿对比度增益和低亮度对比度增益，而C2和N2是由不同的视觉机制产生的。
Transient visual evoked cortical potentials (VECP) were recorded from the scalp of healthy normal trichromats (n = 12). VECPs were elicited by onset/offset presentation of patterned stimuli of two kinds: isochromatic luminance-modulated, and equiluminant red-green modulated, sine wave gratings. The amplitude and latency of the major onset components of the onset/offset VECP were measured and plotted as a function of the logarithm of pooled cone contrast. The early onset components, achromatic C1 and chromatic N1, increase linearly with log contrast, but N1 has a higher contrast gain than C1. The late onset components, achromatic C2 and chromatic N2, have similar contrast gain, and similar response as a function of contrast level: both increase in the low-to-medium range of contrasts and saturate at high contrast levels. In the range of pooled cone contrast tested, C1 and N1 show similar latencies, whilst C2 shows shorter latencies than N2. We suggest that C1 and N1 are generated by the same visual mechanism with high red-green contrast gain and low luminance contrast gain, whilst C2 and N2 are generated by different visual mechanisms.