ネコ視索核より前庭核への直接投射について

Abstract

The nucleus of the optic tract (NOT) serves as an important visuo-motor relay between the retina and preoculomotor structures that mediate horizontal optokinetic nystagmus. In the present study, projections from the NOT in the brainstem were investigated using anterograde and retrograde tracers. Following biocytin injections into NOT, labeled fibers were observed in each of the following efferent pathways: 1) those that project to the contralateral NOT via the posterior commissure; 2) those that course through the nucleus reticularis pontis oralis to terminate the nucleus reticularis tegmenti pontis; and 3) those that descend via the medial lemniscus to the level of the medulla to terminate in the dorsolateral pontine nucleus, nucleus prepositus hypoglossi, descending and medial vestibular nucleus and the dorsal cap of the inferior olive. The projection from the NOT to the vestibula nuclei were demonstrated following WGA-HRP injections into the vestibular nuclei. Direct projections from the NOT to the descending and medial vestibular nuclei may contribute to the residual optokinetic responses of the vestibular nuclei neurons following cerebellar or inferior olivary lesions.