Centrifugal Fibers to the Eye in a Nonavian Vertebrate: Source Revealed by Horseradish Peroxidase Studies

Abstract
A source of efferent fibers to the eye of snakes of the genus Thamnophis has been identified by the use of the retrograde transport of horseradish peroxidase. Cell bodies of the contralateral nucleus of the ventral supraoptic decussation accumulate horseradish peroxidase after intraocular but not intraorbital injections. Intraocular injections also result in anterograde transport of horseradish peroxidase to retinofugal axon terminals. Intraorbital injections result in accumulation of horseradish peroxidase in the cell bodies of the cranial nerve nuclei of extraocular muscles.