Afferent projections to the ventral lateral geniculate nucleus in the cat.

Horseradish peroxidase (HRP) injections were made into the dorsal lateral geniculate nucleus (LGNd) and ventral lateral geniculate nucleus (LGNv) of the cat in order to define afferent projections to LGNv. These were found from the superior colliculus, contralateral LGNv, dorsal median raphe nucleus, locus coeruleus, ipsilateral pretectum, and various portions of visual cortex. While many cortical areas project to LGNv (17, 18, 19, 21 and lateral suprasylvian), the heaviest input arises from areas 17 and 20. The cell bodies of origin are in layer 5 in contrast to layer 6 which projects to LGNd.