Development of receptive field properties of retinal ganglion cells in kittens raised with a convergent squint.

The effects on retinal ganglion cell receptive fields of rearing kittens with convergent squint, surgically induced on the 12th post-natal day, were investigated by utilizing the extracellular single unit recording technique. The data revealed that responses of cross-eyed cat ganglion cells to contrast reversal stimuli were severely depressed and the retinal region exhibiting the best responses varied according to the degree of convergent misalignment of the eyes displayed by each animal. Receptive field sizes of X-type (but not Y-type) units located within 10 degrees of the area centralis of cross-eyed cats were significantly larger than those in normally reared cats. Finally, the encounter rate for units exhibiting non-linearity of spatial summation (Y-type) were much lower in cross-eyed cats. The results suggest developmental alterations in the retinal neurophysiology of common cats reared with a large convergent squint.