Chapter 18 Spinal cord regeneration in adult goldfish: implications for functional recovery in vertebrates

Abstract

Many central nervous system (CNS) neurons damaged by spinomedullary level (SML) crush in adult goldfish extend sprouts that choose a peripheral nervous system (PNS) pathway. This chapter gives suggestion that this inappropriate choice delays, impairs, or prevents recovery of behaviors, including equilibrium and C-starts. If this pathway choice is responsible for the limited regenerative capacity, it may also explain limited behavioral recovery in nonmammalian and mammalian vertebrates alike. The goldfish PNS may present a more permissive environment to regenerating fibers than the CNS after SML crush. Such a pathway preference demonstrates a parallel to mammalian systems and makes the goldfish more valuable as a model system for regeneration. While advances have been made in techniques that allow mammalian CNS neurons to regenerate over distances longer than 1 mm, such as peripheral nerve implants, conditioned media, and antibodies that neutralize inhibitory substances, there is no guarantee that regenerating sprouts will make appropriate pathway choices, that behavioral recovery will result in the return of function or that neurons normally involved in a behavior will contribute equally to the recovery. The adult goldfish nervous system provides an exciting model to address these issues.