RETROGRADE FLUORESCENT MICROSPHERE TRACING OF RETINAL AND CENTRAL AFFERENTS TO THE NUCLEUS OF THE OPTIC TRACT IN PIGMENTED AND ALBINO-RATS

The pretectal nucleus of the optic tract is involved in optokinetic ny stagmus. Albino animals suffer from inverse optokinetic nystagmus, pos sibly due to a smaller number of ipsilateral projections. Animals with laterally placed eyes have an asymmetric nystagmus, attributed to a p resumed lack of binocular cortical input to the nucleus of the optic t ract. Moreover, a direct input from the ipsilateral retina is controve rsial. We investigated the retinal and central afferents to the nucleu s of the optic tract in the rat by retrograde tracing using fluorescen t latex microspheres. Ipsilaterally projecting retinal ganglion cells were observed in pigmented and also in albino rats. Projections from t he visual cortex and primary visual nuclei were demonstrated.