NNNDs indicate a mosaic-like arrangement of spatial RFs. A, NNNDs for brisk sustained, brisk transient, and small transient cells, with ON cells at the top and OFF cells at the bottom. Data are from one retina. Black lines show expected NNNDs for randomly sampled cell locations (see Materials and Methods); dashed lines show the 95% CI. B, p Values from a two-sample Kolmogorov–Smirnov (KS) test for observed NNNDs arising from random cell locations. Fill circles correspond to the data shown in A.