Retinofugal projections in the rufous horseshoe bat, Rhinolophus rouxi.

The retinal projections in the horseshoe bat were studied with anterograde transport of wheat germ agglutinin conjugated to horseradish peroxidase. Retinal fibers clearly terminate bilaterally in the lateral geniculate nuclei, superior colliculus, pretectal area, and nucleus of the optic tract. The suprachiasmatic nucleus and the lateral terminal nucleus of the accessory optic tract receive extremely weak, through bilateral retinal input. No projections to medial and dorsal accessory optic nuclei were found. There was a limited retinal projection to the ipsilateral dorsal geniculate nucleus. The focus of the ipsilateral projection corresponded to a less densely labeled region on the contralateral side. In this study an ipsilateral retinal projection to the anterior superior colliculus is documented for the first time in a Microchiropteran bat. In the contralateral superior colliculus retinal fibers terminate in a patch-like pattern at caudal levels.