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 signaloise ratio (compared to the signaloise 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 signaloise ratio improves by a constant factor. The signaloise improvement factor for beta ganglion cells in cat retina is about 4.
展开▼
