Widespread regeneration of central axons through the central nervous system of the goldfish

The ability of neurons in the brain of the goldfish to regenerate their axons was examined using anterograde and retrograde axonal tracing methods. It was found that all neurons in the thalamus and brainstem that project to the optic tectum can regenerate their axons after removal of the tectal lobe, and that their axons can often grow for considerably greater distances than they normally extend. In addition, they can penetrate (and, presumably, innervate) their normal target tissue, even if it is displaced into an ectopic location.