 The evidence for subgroups of alpha cells, and corresponding specificity in their projections, is interesting but underdeveloped. In the case of the OFF-transient alpha cells, there is evidence for anatomical tiling based on SMI00 labeling (Bleckert, 0000). Did you record from cells in the different subgroups in the same retina? Given how much is known about these cell types from past work, and given the strong role that tiling plays in what we know about the organization of different RGC types, more evidence is needed to reach the conclusion that the cells can be subdivided into functionally distinct groups.  0\) Comparison of functional properties of RGCs and downstream projections  Figure 0 compares responses to expanding spots of RGCs with downstream projection areas. Interpretation of this comparison difficult since the kinetics of the retinal responses are slower than those in the brain (particularly the Pbg). I would consider saving this comparison for another paper where it can be developed more completely.  The recent paper from Roson et al., (0000) is highly relevant for the present work and should be included in the Discussion