THE EFFERENT PROJECTIONS OF THE SUPERIOR COLLICULUS IN THE RAT.A STUDY WITH ARG AND WGA-HRP TECHNIQUES / 解剖学报

ABSTRACT

In the present study ~3H-Leucine or WGA-HRP was injected into the superior colliculus of one side in the rat.The terminal areas of the efferent projection fibers from the superior colliculus were examined. The efferent fibers of the superfical layer of the superior colliculus descended ipsilaterally to terminate in the parabigeminal nucleus(predominantly the dorsal and ventral part of the same side)and dorso-lateral part of the ipsilateral pontine nucleus.Ascending projections terminated to the medial geniculate nucleus,the posterior pretectal nucleus and latero-posterior nucleus of the thalamus(all bila- terally,but with ipsilateral predominance),the ipsilateral medial and lateral optic nuclei,and the dorsal and ventral lateral geniculate nucleus.In addition,labeled granules were also found in bilateral optic tracts and the optic chiasma. The efferent fibers of the middle and deep layers terminated to the ipsilateral central gray,the nucleus of Darkschewitsch,the interstitial nucleus of Cajal,the cuneiform nucleus and the contralateral superior colliculus.Ascending fibers ter- minated to the medial geniculate nucleus,the suprageniculate nucleus,the anterior- pretectal nucleus,the postero-lateral nucleus of the thalamus(all bilaterally,but more on the ipsilateral side),the parafascicular nucleus,the zona incerta,the ventral nucleus of the thalamus(all ipsilaterally).Descending fibers terminated to ipsilateral parabigeminal area and the parabigeminal nucleus,the dorso-lateral part of the pontine nucleus,the lateral part of the inferior colliculus,the reticular formation of the medulla oblongata and pons,and the lateral part of the inferior olive.The fibers terminated also to contralateral nuclei such as the parabigeminal nucleus,the medial part of the reticular formation of the medulla oblongata and ports,the medial accessory nucleus of the inferior olive,the anterior horn of the cervical spinal cord.