Abstract
Retrograde axonal transport of horseadish peroxidase from areas 17 and 18 of the cat's visual cortex labels, principally, the small (X) and large (Y) cells, respectively, of the lateral geniculate nucleus. Quantitative analysis of the sizes of these morphologically identified neurons after monocular deprivation shows that the arrest of cell growth in the deprived laminae involves mainly Y cells.