We investigated the pattern transneuronally transported [3H]proline to the visual cortex of normal and deprived marmosets (Callithrix jacchus). In the normal marmoset a continuous band of label was evident within layer IV of striate cortex. Following injection of the closed eye of deprived marmosets, distinct fluctuations of label were apparent over the base of layer IV in both hemispheres. These results support the hypothesis that the presence of ocular separation of geniculo-striate afferents is a feature common to all primates.