Elimination of ipsilateral retinotectal projections in mono-ophthalmic chick embryos

There are two transient ipsilateral retinotectal projections in the chick embryo: a normal one, appearing with a similar projection pattern in both binocular and monocular embryos, and an additional abnormal projection appearing only in mono-ophthalmic embryos. The development and the elimination of the ipsilateral retinotectal projections in mono-ophthalmic chick embryos was investigated using horseradish peroxidase (HRP) and the fluorescent dye Rhodamine-B-Isothiocyanate (RITC) as tracers for axonal pathways. The mechanisms involved in the elimination of the ipsilateral fibers are discussed.