Pluvinage V, Green D G
Vision Research Laboratory, University of Michigan, Ann Arbor 48109.
Vision Res. 1990;30(5):683-91. doi: 10.1016/0042-6989(90)90094-2.
The effect of coupling on the intensity-response functions for full field and for slit stimuli was studied by comparing the shapes of the curves obtained from several strongly coupled red cones of turtle with that of one very weakly coupled cone. The full field V-log I curves could be fitted by a Michaelis-Menten relationship, regardless of the strength of the coupling. For the weakly coupled cone the slit V-log I could also be fitted by a Michaelis-Menten curve. For strongly coupled cones a major portion of the curve (1.2-2 log units of intensity) was better fitted by V oc Im. For centered slits "m" was 0.5. With increased distance between the slit and the center of the receptive field "m" was found to increase slightly. The results were analyzed in terms of a theory in which the shape of the slit intensity-response curves arises from scattered light progressively recruiting neighboring cone responses. An analytical formulation of this idea is presented and a plausible light distribution function which supports the recruitment hypothesis is derived. A numerical model of the cone network, which includes the effect of scattering and transduction saturation, accounts well for all of the experimental data obtained with single and paired slits.
通过比较从几只强耦合的海龟红色视锥细胞以及一只非常弱耦合的视锥细胞获得的曲线形状，研究了耦合对全场和狭缝刺激强度响应函数的影响。全场V-log I曲线可以用米氏关系拟合，与耦合强度无关。对于弱耦合视锥细胞，狭缝V-log I也可以用米氏曲线拟合。对于强耦合视锥细胞，曲线的主要部分（强度的1.2 - 2对数单位）用V oc Im拟合得更好。对于中心狭缝，“m”为0.5。随着狭缝与感受野中心之间距离的增加，发现“m”略有增加。根据一种理论对结果进行了分析，在该理论中，狭缝强度响应曲线的形状源于散射光逐渐招募相邻视锥细胞的响应。提出了这一想法的解析表达式，并推导了支持招募假说的合理光分布函数。一个包含散射和转导饱和效应的视锥细胞网络数值模型，很好地解释了用单狭缝和双狭缝获得的所有实验数据。
