[Study on the origin of vestibular neurons projecting to the spinal cord using retrograde labelling technique of horseradish peroxidase].
In spite of a large number of electrophysiological studies into the vestibulospinal (VS) effects on the spinal cord, there are far fewer anatomical studies on the VS projections. The present study was undertaken to determine the origins and descending pathways of VS neurons in the cat, using a retrograde labelling technique of horseradish peroxidase (HRP) combined with a lesion in the lower brainstem. HRP was applied unilaterally into the cervical or lumbar spinal cord and either the medial longitudinal fasciculus (MLF) or the lower medulla oblongata, sparing the MLF, was dissected. In all cases, HRP-labelled neurons were located in two distinct areas of the vestibular nuclear complex, the rostral and caudal areas. In the rostral area, HRP-labelled neurons after dissection of the MLF appeared in the ipsilateral lateral (LN), medial (MN) and descending nuclei (DN), on the same side as HRP insertion into the spinal cord, but somatotopical arrangement was not seen in the present study. Labelled neurons in the rostral part after impairment of a wide area of the lower medulla, though sparing the MLF, were seen bilaterally in the areas bordering the LN, MN, DN and superior nuclei. In the caudal area, HRP-labelled neurons were seen bilaterally in the caudal thirds of the MN and DN, and these projected to the lumbar spinal cord. Therefore the origins and descending pathways of the VS tracts were considered to be different from those shown in previous anatomical studies.
Hata
Y
Y
Department of Otolaryngology, Tokyo Medical and Dental University.
D000818:Animals; D002415:Cats; D006651:Histocytochemistry / Q000379:methods; D006735:Horseradish Peroxidase / Q000008:administration & dosage; D009434:Neural Pathways / Q000166:cytology; D009474:Neurons / Q000166:cytology; D013116:Spinal Cord / Q000166:cytology*; D014726:Vestibular Nuclei / Q000166:cytology*
D006735:Horseradish Peroxidase