Abstract: Projection from the vestibular nuclei to the spinal cord was examined following injection of cholera toxin subunit B at various levels of the spinal cord in the rat. The results were as follows: ① The majority of the labeled cells were seen in the caudal ventral of LVN, caudal of DVN and MVmc of MVN from the injections into the upper cervical segment. ② The labeled cells were only seen in the caudal ventral of LVN, and distributed diffusely in the DVN and MVN from the injections into the cervical enlargement segment. ③ The labeled cells were distributed in all parts of LVN and DVN, especially densest in the rostral dorsal of LVN, and seldom seen in the MVmc of MVN from the injections into the thoracic and lumbar segment. ④ The labeled cells from the injections into the sacral segment distributed sparsely in the LVN and DVN. The result indicates that the fibers of origin from the DVN and LVN projected directly to the sacral segment, while the fibers of origin from the MVN only projected to the upper lumbar segment.

Key words: vestibular nucleus, spinal cord, cholera toxin subunit B(CTBp