Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois.
Invest Ophthalmol Vis Sci. 2014 Feb 4;55(2):719-27. doi: 10.1167/iovs.13-13252.
We determined the relative contributions of rods, cones, and melanopsin to pupil responses in humans using temporal sinusoidal stimulation for light levels spanning the low mesopic to photopic range.
A four-primary Ganzfeld photostimulator controlled flicker stimulations at seven light levels (-2.7 to 2 log cd/m(2)) and five frequencies (0.5-8 Hz). Pupil diameter was measured using a high-resolution eye tracker. Three kinds of sinusoidal photoreceptor modulations were generated using silent substitution: rod modulation, cone modulation, and combined rod and cone modulation in phase (experiment 1) or cone phase shifted (experiment 2) from a fixed rod phase. The melanopsin excitation was computed for each condition. A vector sum model was used to estimate the relative contribution of rods, cones, and melanopsin to the pupil response.
From experiment 1, the pupil frequency response peaked at 1 Hz at two mesopic light levels for the three modulation conditions. Analyzing the rod-cone phase difference for the combined modulations (experiment 2) identified a V-shaped response amplitude with a minimum between 135° and 180°. The pupil response phases increased as cone modulation phase increased. The pupil amplitude increased with increasing light level for cone, and combined (in-phase rod and cone) modulation, but not for the rod modulation.
These results demonstrate that cone- and rod-pathway contributions are more predominant than melanopsin contribution to the phasic pupil response. The combined rod, cone, and melanopsin inputs to the phasic state of the pupil light reflex follow linear summation.
我们通过对跨越低中等到光适应范围的光水平进行时间正弦刺激，确定了棒状细胞、视锥细胞和黑视蛋白对人类瞳孔反应的相对贡献。
使用四原色全视野光刺激器控制闪烁刺激，在七个光水平（-2.7 至 2 log cd/m²）和五个频率（0.5-8 Hz）下进行。使用高分辨率眼动追踪仪测量瞳孔直径。通过静默替换生成三种正弦光感受器调制：棒状细胞调制、视锥细胞调制以及与固定棒状细胞相位同相（实验 1）或视锥细胞相位相移（实验 2）的棒状细胞和视锥细胞组合调制。为每种条件计算了黑视蛋白激发。使用矢量和模型来估计棒状细胞、视锥细胞和黑视蛋白对瞳孔反应的相对贡献。
从实验 1 中，在三个调制条件下，瞳孔频率响应在两个中等到低光水平下在 1 Hz 处达到峰值。分析组合调制的棒状细胞-视锥细胞相位差（实验 2）确定了一个 V 形响应幅度，最小值在 135°至 180°之间。随着视锥细胞调制相位的增加，瞳孔反应相位增加。随着光水平的增加，瞳孔幅度增加对于视锥细胞和组合（同相棒状细胞和视锥细胞）调制，但对于棒状细胞调制则不然。
这些结果表明，与黑视蛋白相比，视锥细胞和棒状细胞通路的贡献对相敏瞳孔反应更为重要。向相敏瞳孔光反射的相敏状态输入的组合棒状细胞、视锥细胞和黑视蛋白输入遵循线性求和。
