Rearing cats with eyelid suture has both early and late effects on cells in the lateral geniculate nucleus

We have assessed the effects of duration of infant-onset deprivation, and therefore the age of the subject at the time of data collection, on the physiology and morphology of cells in the lateral geniculate nucleus (LGN) of cats. Twenty-two kittens underwent lid suture. Electrophysiological experiments were performed in 12 of these subjects when they were between 5 and 16 months of age. The remaining 10 cats were studied between 17 and 29 months. In 16 of these same subjects we also measured LGN soma sizes to permit a direct within-subject comparison of the morphological and physiological effects of lid suture. Physiological data from cats recorded before 17 months of age showed a reduction in the encounter rate of Y-cells in deprived LGN laminae. In contrast, none of the cats which were 17 months or older at the time of recording showed a reduction in the encounter rate of deprived Y cells, giving the appearance of a more normal X/Y-cell ratio. Preliminary observations suggest that these late changes in the physiological effects of deprivation are not due to a recovery of Y-cells, but are more likely due to the superimposition of a reduction in the encounter rate for X-cells known to be typical of a variety of adult-onset deprivations. Finally, the physiological and morphological differences between non-deprived and deprived LGN laminae are correlated for the individual subjects.