Ganglion cells and retinopetal fibers of the larval lamprey retina: an HRP ultrastructural study.

The ultrastructure of ganglion cells and centrifugal fibers of the larval lamprey retinas were studied using horseradish peroxidase (HRP) as a marker. Larval ganglion cells were found both in the inner nuclear layer and the inner plexiform layer of the differentiated retina, and also were present in the undifferentiated retina. Direct photoreceptor-ganglion cell contacts and the presence of centrifugal fibers are described for the first time in the lamprey. The centrifugal fibers contact directly with ganglion cells in this species.