The field adaptation of the human rod visual system.
The field adaptation of the human rod visual system.
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人体视杆视觉系统的现场适应。
DOI：
10.1113/jphysiol.1992.sp018926
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Stockman,A
中科院分区：
文献类型：
--
作者：
Sharpe,LT;Fach,CC;Stockman,A
1.在距中心凹12°的视网膜区域测量递增阈值，目标持续时间为200ms，直径6°，叠加在不同强度和波长的背景场上。测量是在杆状隔离条件下进行的，五名正常观察者和一名典型的、完全消色差的观察者没有锥体功能。2.在正常的三原色观察者中，阈值随背景强度的升高随背景波长的变化而变化。在450、520和560 nm背景下，对数坐标的平均斜率(0.78+/-0.04，S.D.)其斜率与背景波长无关(0.79+/-0.03)，但在640 nm背景下更接近韦伯定律(0.91+/-0.02)。这表明，棒对增量靶的敏感性不仅取决于棒中的量子吸收，还取决于棒和锥体中的量子吸收。3.还测量了缺乏一个或多个锥体类别的各种色盲观察者的视杆递增阈值：蓝锥体单色垫、四个后视镜和原视镜。对于蓝锥单色板，如消色差板，其增量阈值曲线的斜率随背景波长的变化而恒定。对于重离子和正离子，斜率随波长的增加而增大。然而，原锥的斜率增加较小，这与希氏锥体对长波长光的敏感度较低一致。4.视杆的田间适应依赖于视锥，在视场混合实验中，增量阈值是在双色背景下测量的，在无声替代实验中，背景对视锥或视杆的影响是相等的，但不是两种背景都立即相互替换。
1. Incremental thresholds were measured in a retinal region 12 deg temporal from the fovea with a target of 200 ms in duration and 6 deg in diameter superimposed on background fields of various intensities and wavelengths. Measurements were made under rod‐isolation conditions in five normal observers and in a typical, complete achromat observer who had no cone function. 2. The rise in threshold with background intensity changes with background wavelength in the normal trichromat observers. On 450, 520 and 560 nm backgrounds the average slope in logarithmic co‐ordinates (0.78 +/‐ 0.04, S.D.) is similar to that found for the achromat‐‐whose slope is independent of background wavelength (0.79 +/‐ 0.03)‐‐but on a 640 nm background it more nearly approaches Weber's law (0.91 +/‐ 0.02). This indicates that the sensitivity of the rods to an incremental target is not determined by quantal absorptions in the rods alone but by quantal absorptions in both the rods and the cones. 3. Rod incremental thresholds were also measured in various colour‐blind observers lacking one or more of the cone classes: a blue‐cone monochromat, four deuteranopes and a protanope. For the blue‐cone monochromat, like the achromat, the slope of the increment threshold curve is constant with background wavelength. For the deuteranopes and the protanope, like the normal, the slope increases with wavelength. The protanope, however, shows a smaller increase in slope, consistent with the lower sensitivity of his cones to long‐wavelength light. 4. The dependence of the field adaptation of the rods on the cones was confirmed by field‐mixture experiments, in which the incremental threshold was measured against bichromatic backgrounds, and in silent substitution experiments, in which backgrounds equated for their effects on either the cones or the rods but not both were instantaneously substituted for one another.