THE PRIMARY VISUAL-SYSTEM OF ADULT LIZARDS DEMONSTRATES THAT NEUROGENESIS IS NOT OBLIGATORILY LINKED TO CENTRAL NERVE REGENERATION BUT MAY BE A PREREQUISITE FOR THE RESTORATION OF MAPS IN THE BRAIN

Following optic nerve crush in the adult lizard Ctenophorus ornatus, m ost retinal ganglion cells regrow their axons into visual brain centre s: however, the regenerated projections lack retinotopic order and the animals are blind via the experimental eye, Here we have used 3H-thym idine autoradiography to demonstrate that cell division is no longer t aking place in the retina of normal adult lizards. We conclude that th e optic nerve can regenerate in lizard even though cells are no longer being added to the retina. However, continued retinal neurogenesis ma y be linked to the ability to restore topographic maps. (C) 1998 Elsev ier Science Ltd. All rights reserved.