Errant optic axons in the normal goldfish retina reach retinotopic tectal sites

Optic axons in the goldfish retina generally run radially from their origins to the optic nerve. However, horseradish peroxidase (HRP), introduced into small groups of axons through lesions in the tecta of normal fish, consistently filled some which ran parallel to the retinal margin for long distances before turning centrally. Since all the HRP-filled ganglion cells lay close together, their axons evidently reached adjacent tectal sites by these widely divergent routes.