Regeneration in the developing optic nerve: correlating observations in the opossum to other mammalian systems.

Dr. Robert E. MacLaren,
Division of Ophthalmology, Royal Berkshire Hospital, Reading, United Kingdom

The opossum offers an ideal model in which to investigate properties of mammalian optic nerve regeneration early in development. During the postnatal periad, ganglion cells lesioned in the retina can regenerate and reconnect to central targets. Ganglion cells regenerating from the temporal retina decussate at the optic chiasm sugesting that regenerating axons are able to re-interact with appropriate guidance cues at this point. A critical developmental period exists, long before the onset of myelination, at which regeneration ceases. Studies into the properties of visual pathway development precisely at this critical period may help in the understanding as to why optic nerve regeneration does not occur in the adult.