| Abstract: | Following tectal lobe removal in the goldfish, optic fibers, which are sectioned by the surgery, regenerate through various abnormal pathways to both the optic tectal lobe which remains and to various non-optic sites in the brain. In this communication we present anatomical evidence that regenerated optic fibers in many of these pathways atrophy or disappear within several months after surgery. By contrast, in some pathways the regenerated fibers persist for at least 1.5 years. We suggest that the majority of fibers which persist for long periods do so because they have reached the remaining tectal lobe and been able to make synapses there.The results from this system are briefly compared to those which have been obtained in studies of regeneration in the peripheral nervous system and parallels between the two are noted. |
