Direct projection from the nucleus of the optic tract to the medial vestibular nucleus in the cat.
The nucleus of the optic tract (NOT) serves as an important visuo-motor relay between the retina and preoculomotor structures that mediate optokinetic nystagmus. In the present study, the efferent targets of NOT were investigated using biocytin as an anterograde tracer. 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 in 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, medial vestibular nucleus and the inferior olive. Direct projections from the NOT to the medial vestibular nucleus may contribute to the residual optokinetic responses of the vestibular nucleus neurons following cerebellar or inferior olivary lesions.
Watanabe
S
S
Department of Otolaryngology, St. Marianna University School of Medicine, Kawasaki, Japan.
Kato
I
I
Sato
S
S
Norita
M
M
D000818:Animals; D002415:Cats; D006651:Histocytochemistry; D008239:Lysine / Q000031:analogs & derivatives; D017120:Nystagmus, Optokinetic / Q000502:physiology; D017729:Presynaptic Terminals / Q000502:physiology; D014726:Vestibular Nuclei / Q000166:cytology / Q000502:physiology*; D014795:Visual Pathways / Q000166:cytology / Q000502:physiology*
C013411:biocytin; D008239:Lysine