HUMAN CONES APPEAR TO ADAPT AT LOW-LIGHT LEVELS - MEASUREMENTS ON THE RED-GREEN DETECTION MECHANISM
HUMAN CONES APPEAR TO ADAPT AT LOW-LIGHT LEVELS - MEASUREMENTS ON THE RED-GREEN DETECTION MECHANISM
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DOI：
10.1016/0042-6989(95)00069-c
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发表时间：
1995-11-01
期刊：
影响因子：
1.8
通讯作者：
KRONAUER, RE
中科院分区：
文献类型：
--
作者：
CHAPARRO, A;STROMEYER, CF;KRONAUER, RE
最近的生理证据表明，视锥细胞在低光条件下不适应光，为了评估在低光条件下视锥细胞是否具有适应光的选择性，分离了红绿检测机制，在不同颜色的适应场上，以不同的固定振幅比刺激L和M视锥细胞测量阈值，在L和M视锥对比坐标中绘制阈值。红绿机制对每个彩色场上L和M锥体对比度的等权重差异作出反应，证明了L和hi锥体信号的等效韦伯适应，L和M锥体信号独立适应低至60个有效区（例如M-锥体区）的光照水平。由于这种适应完全是对视锥类型的选择性适应，这表明视锥本身是光适应的。红色区域上的红-绿检测轮廓从视锥对比坐标的原点进一步偏移，揭示了在随后的光谱对抗位点的额外灵敏度损失。这种第二位点效应可能来自净“红”或“绿”信号，该信号表示L和M视锥在稳定的、彩色适应场。这种微分超偏振与L锥和M锥的等效韦伯自适应是相容的。
Recent physiological evidence suggests that cones do not light adapt at low light levels, To assess whether adaptation is cone-selective at low light levels, the red-green detection mechanism was isolated, Thresholds were measured with a large test flash, which stimulated the L and M cones in different fixed amplitude ratios, on different colored adapting fields, Thresholds were plotted in L and M cone contrast coordinates, The red-green mechanism responded to an equally-weighted difference of L and M cone contrast on each colored field, demonstrating equivalent, Weberian adaptation of the L and hi cone signals, The L and M cone signals independently adapted for illuminance levels as low as 60 effective trolands (e.g, M-cone trolands). Since this adaptation is entirely selective to cone type, it suggests that the cones themselves light-adapt, The red-green detection contour on reddish fields was displaced further out from the origin of the cone contrast coordinates, revealing an additional sensitivity loss at a subsequent, spectrally-opponent site, This second-site effect may arise from a net ''red'' or ''green'' signal that represents the degree to which the L and M cones are differently hyperpolarized by the steady, colored adapting field. Such differential hyperpolarization is compatible with equivalent, Weberian adaptation of the L and M cones.