Synaptic connections of cortical and retinal terminals in the superior colliculus of the rabbit: an electron microscopic double labelling study.

Retinal and cortical afferents to the superior colliculus of the rabbit were labelled simultaneously by injecting 3H-leucine into the right eye and HRP into the left visual cortex. It could be shown that there is some convergence of retinal and cortical input onto common postsynaptic elements in the superficial grey, but these cases were found to be rather rare indicating that most afferents from the retina and the visual cortex terminate either on different postsynaptic cells or on different parts of common postsynaptic cells.