 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.  