Cell growth in the lateral geniculate nucleus of kittens following the opening or closing of one eye

Closing one eye of kittens at 23 days after birth resulted in paler Nissl staining of the deprived cells in the lateral geniculate nucleus (LGN) that was detectable two days later. Differences between the two sides of the brain in mean cell area increased to a peak in binocular lamina A at 4--6 days after eyelid suture, and then fell to a trough at eight days before rising progressively to a higher level at 31 days. In lamina A1 the peak and trough were later. Opening one eye of kittens after 23 days of binocular closure from birth resulted in more intense Nissl staining of the stimulated cells in the LGN that was detectable four days later. The stimulated cells grew faster than the cells connected to the eye that remained closed, and this differential growth reached a peak at 17 days in binocular lamina A and at 21 days in lamina A1 before falling to a trough at 26--31 days. These results are compared with the time course of anabolic changes that have been measured in other neurons during stimulation. The coefficient of variation of cell size was computed and found to be slightly decreased for deprived cells and increased for stimulated cells. This suggests that larger cells changes their sizes proportionately more than smaller cells. The cells were measured in fronzen sections without shrinkage, and the areas are at least 25% larger than those reported previously after paraffin or celloidin embedding.