A crossed parabigemino-lateral geniculate projection in rats blinded at birth.

Anatomical techniques are used to demonstrate a projection from the parabigeminal nucleus (PBG) to the contralateral dorsal lateral geniculate nucleus (dLGN) in adult pigmented rats which had been bilaterally enucleated at birth. No similar pathway is detected in normal animals. Ultrastructural examination of degeneration in dLGN of blinded rats after contralateral PBG lesion reveals a similarity of the PBG terminals to "replacement terminals" seen in dLGN of anophthalmic or neonatally enucleated mice (Cullen and Kaiserman-Abramof 1976).