Displaced ganglion cells in the retina of the rat

The distribution, laterality of projection, and perikaryal sizes of displaced ganglion cells (DGCs) were examined in whole-mounted retinae after massive unilateral injections of horseradish peroxidase along the optic tract in pigmented rats. The DGCs were found predominantly in the lower temporal periphery of the retina. Nearly all DGCs labeled had contralaterally projecting axons. The sizes of the labeled DGCs spanned the range of ordinary ganglion cells, but few middle-sized DGCs were labeled. The results support the hypothesis that displaced ganglion cells are late-developing neurons that do not complete their migration toward the ganglion cell layer during retinal histogenesis.