Absence of sprouting by retinogeniculate axons after chronic focal lesions in the adult cat retina.

Focal lesions were placed in the retina of adult cats in order to denervate partially the laminae of the lateral geniculate nucleus (LGN). Retinogeniculate projections were assessed after survival times of from 5 days to 2 years by means of either reduced silver staining for degeneration or autoradiographic labelling. Filling of the lesion-denervated zones by 'sprouts' from the intact retinofugal fibers was not observed, even in the brains of animals with long-term lesions. It was concluded that the retinogeniculate projection in adult cat does not display any significant ability to sprout into denervated regions.