Effects of reduced numbers of lateral geniculate Y-cells on development of ocular dominance in cat striate cortex

In the companion study ( Dev. Brain Res. , 34 (1987) 223–233), we showed that a monocular injection of antibodies against ox large retinal ganglion cells produces a 53% (low concentration) to 82% (high concentration) loss of Y-cells in lateral geniculate nucleus (LGN) layers A and A 1 that receive inputs from the antibody-injected eye. At the same time, the percentage of LGN X-cells is unaffected. In the present study, we investigated the effect of this monocular antibody-induced reduction of LGN Y-cells on the development of ocular dominance in striate cortex. Four-week-old kittens were given an intraocular injection of either a low (110 μg/33 μl volume) or a high (333 μg/33 μl volume) concentration of antibodies and single-cell recordings were carried out in striate cortex 33–65 weeks later. Following an injection of either antibody concentration, we found only slight abnormalities in striate cortex ocular dominance compared to normal adult cats. There was a small, but significant, decrease in the percentage of binocularly driven cells and a concomitant increase in the percentage of cells driven exclusively by the normal or control-injected eye. No ocular dominance abnormalities were found in kittens injected monocularly with control γ-globulins, indicating that the changes are due to effects of the antibodies. The changes in cortical ocular dominance produced by early antibody treatment are very different from those produced by rearing with monocular deprivation (MD) despite a similar loss of LGN Y-cells in the two conditions. This suggests that an initial (primary) monocular loss of LGN Y-cells in young kittens is not sufficient to alter cortical ocular dominance in a manner similar to that found after MD. The results thus argue against the hypothesis that the MD-induced loss of response to the deprived eye in striate cortex is secondary to a Y-cell loss in the LGN.