Disruption of retinal axon ingrowth by ablation of embryonic mouse optic chiasm neurons.

Mouse retinal ganglion cell axons growing from the eye encounter embryonic neurons at the future site of the optic chiasm. After in vivo ablation of these chiasm neurons with a monoclonal antibody and complement, retinal axons did not cross the midline and stalled at approximately the entry site into the chiasm region. Thus, in the mouse, the presence of early-generated neurons that reside at the site of the future chiasm is required for formation of the optic chiasm by retinal ganglion cell axons.