The naso‐temporal division of the cat's retina re‐examined in terms of Y‐, X‐ and W‐cells

In the cat, as in all mammals, optic nerve fibres decussate only partially, so that some of the ganglion cells in one retina project to the contralateral side of the brain, and some to the ipsilateral side. The retinal distribution of ipsi‐ and contralaterally projecting ganglion cells, described in a previous study, has been re‐examined in the context of the recent classification of cat retinal ganglion cells into three major types (W‐, X‐ and Y‐cells). Evidence is presented of significant differences between the three cell types in the retinal distribution of ipsi‐ and contralaterally projecting cells. The pattern of naso‐temporal division of retina described previously thus appears to be a composite of the different patterns of the three cell types. Functional implications of these different patterns are considered.