The ipsilateral retinotectal projection in normal and albino channel catfish.

The retinal projection to the ipsilateral optic tectum was examined first in normal channel catfish. After unilateral optic nerve section and horseradish peroxidase (HRP) application, a sparse retinal projection was seen in the ipsilateral optic tectum. When HRP was applied to the ipsilateral rostral tectum, labeled ganglion cells were observed in the ventrotemporal quadrant of the ipsilateral eye. Electrophysiological mapping of the ipsilateral projection confirmed that cells in the temporal retina projected to the rostral tectum. When albino catfish were examined using these techniques, the ipsilateral retinotectal projection was found to be much sparser than the ipsilateral projection of normal catfish.