Retention of retinal axon collateral is responsible for induced ipsilateral retinotectal projections in adult goldfish.
In normal goldfish, optic axons innervate only the contralateral optic tectum. When one eye was enucleated and the optic nerve of the other eye crushed, the regenerating optic axons innervated both optic tecta. We studied the presence of bilaterally projecting retinal ganglion cells by double retrograde cell labeling methods using Nuclear Yellow and True Blue dyes. About 10% of the retinal ganglion cells were double labeled and these cells were found throughout the retina. In addition, HRP application to the ipsilateral tectum revealed retrogradely-labeled retinal ganglion cells of all morphological types. These results suggest that induced ipsilateral projections are formed by regenerating axon collaterals and that all cell types are involved in the generation of normal mirror image typography.
Sharma
S C
SC
Department of Ophthalmology, New York Medical College, Valhalla 10595.
Tsai
C
C
D000818:Animals; D001369:Axons / Q000502:physiology; D006054:Goldfish / Q000502:physiology*; D009416:Nerve Regeneration; D009473:Neuronal Plasticity; D009900:Optic Nerve / Q000502:physiology; D012165:Retinal Ganglion Cells / Q000502:physiology*; D013477:Superior Colliculi / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology*