Tsukamoto Y, Smith R G, Sterling P
Department of Anatomy, School of Medicine, University of Pennsylvania, Philadelphia 19104.
Proc Natl Acad Sci U S A. 1990 Mar;87(5):1860-4. doi: 10.1073/pnas.87.5.1860.
The signals in neighboring cones are partially correlated due to local correlations of luminance in the visual scene. By summing these partially correlated signals, the retinal ganglion cell improves its signal/noise ratio (compared to the signal/noise ratio in a cone) and expands the variance of its response to fill its dynamic range. Our computations prove that the optimal weighting function for this summation is dome-shaped. The computations also show that (assuming a particular space constant for the correlation function) ganglion cell collecting area and cone density are matched at all eccentricities such that the signal/noise ratio improves by a constant factor. The signal/noise improvement factor for beta ganglion cells in cat retina is about 4.
由于视觉场景中亮度的局部相关性，相邻视锥细胞中的信号存在部分相关性。通过对这些部分相关的信号进行求和，视网膜神经节细胞提高了其信噪比（与单个视锥细胞中的信噪比相比），并扩展了其响应的方差以填充其动态范围。我们的计算证明，这种求和的最佳加权函数是圆顶形的。计算还表明（假设相关函数有特定的空间常数），神经节细胞的收集区域和视锥细胞密度在所有偏心率下都相互匹配，从而使信噪比提高一个恒定因子。猫视网膜中β神经节细胞的信噪比提高因子约为4。
