Termination of retinal fibers in lateral preoptic and hypothalamic areas of the crab-eating monkey, Macaca irus.

After a monocular injection of tritiated proline into the vitreous chamber of the eye, the distribution of labeled retinal termination in the hypothalamus of the crabeating monkey was investigated by autoradiography. The results indicated that a few retinofugal fibers might terminate bilaterally in the lateral hypothalamic areas through the level of the anterior commissure to the infundibulum as well as the suprachiasmatic nuclei. The labeled fibers to the lateral hypothalamic area seemed to leave the dorsocaudal border of the optic chiasma in a dorsolateral direction and then coursed both rostrally and caudally above the supraoptic nucleus: these fibers might progressively diminish in number at more rostral and caudal levels. Further, small clusters of developed silver grains were found bilaterally in the caudal part of the lateral preoptic nuclei.