Usui S, Stark L
Biol Cybern. 1982;45(1):13-21. doi: 10.1007/BF00387209.
In this paper we present new experimental results that show pupillary noise to be multiplicative in a particular fashion with greatest variance in midrange and smaller variance at high and low ranges. This confirms the finding of multiplicative noise by Stanten and Stark (1966), but modifies and extends the relationship they suggested between standard deviation and mean pupil diameter. We propose a parametric model of the iris muscle which not only describes the static characteristics of pupil response to given stimuli, but also explains its random fluctuations in terms of probability density functions. We emphasize the point that the range nonlinearity is not due to decreased gain at the extrema of the pupil range, but is operational over a wide portion of the pupillary behavioral range, hence its name--"expansive range nonlinearity". We conclude that noise amplitude, which is a function of the pupil diameter, closely parallels the changes in deterministic gain. Thus pupil noise can be simply considered as cross-talk additive Gaussian noise injected into the pupil system at midbrain level.
在本文中，我们展示了新的实验结果，这些结果表明瞳孔噪声以一种特定方式呈乘法性，在中等范围具有最大方差，在高范围和低范围方差较小。这证实了斯坦滕和斯塔克（1966年）关于乘法性噪声的发现，但修改并扩展了他们所提出的标准差与平均瞳孔直径之间的关系。我们提出了一种虹膜肌肉的参数模型，该模型不仅描述了瞳孔对给定刺激的静态响应特性，还根据概率密度函数解释了其随机波动。我们强调，范围非线性并非由于瞳孔范围极值处增益降低，而是在瞳孔行为范围的很大一部分上起作用，因此其名称为——“扩展范围非线性”。我们得出结论，作为瞳孔直径函数的噪声幅度与确定性增益的变化密切平行。因此，瞳孔噪声可简单地视为在中脑水平注入瞳孔系统的串扰加性高斯噪声。
