Nerve fiber layer of the owl monkey retina: retinotopic organization.

The organization of nerve fiber bundles, stained by microelectrode injection of horseradish peroxidase, was examined in the retina of the owl monkey. Fibers were traced across the retina in whole mounts and serial sections to evaluate their retinotopic order. Long nasal fibers showed little tendency to wander among bundles but were distributed randomly within the bundles near the disc. Long arcuate and papillomascular fibers, in sharp contrast, spread laterally among many bundles as they approached the disc, but were segregated within the bundles in a scleral position. These results indicate that horizontal retinotopy among bundles is well developed in nasal but not temporal retina; vertical retinotopy within bundles is well developed in temporal but not nasal retina of the owl monkey. These findings are significantly different from those of a recent study of the macaque monkey.