Pflieger J F, Dubuc R
Centre de Recherche en Sciences Neurologiques, Université de Montréal, Montréal, Québec H3C 3J7, Canada.
J Comp Neurol. 2000 Nov 13;427(2):255-73. doi: 10.1002/1096-9861(20001113)427:2<255::aid-cne7>3.0.co;2-1.
The distribution of vestibular primary afferents as well as their relationship with vestibulospinal and other brainstem neurons were studied in lampreys using anatomical tracers. Afferents from the anterior (aVIIIn) and the posterior (pVIIIn) branches of the vestibular nerve were located mainly in the ventral nucleus of the octavolateral area. The relationship between afferents and vestibulospinal neurons was studied by applying one fluorescent tracer to the whole vestibular nerve or one of its branches and applying another tracer to the spinal cord. Some afferents showed large, bulb-like enlargements (bulbs) and about 20 of these were found in the anterior and the intermediate octavomotor nucleus, whereas about 40 were found in the posterior octavomotor nucleus. Some of the bulbs made apparent contact with vestibulospinal neurons in the intermediate octavomotor nucleus and originated mostly from the aVIIIn, whereas bulbs in the posterior octavomotor nucleus originated from the pVIIIn. Applications of biocytin to hemisegments of rostral spinal cord labeled vestibulospinal neurons located in the ipsilateral intermediate octavomotor nucleus and the contralateral posterior octavomotor nucleus. In addition, vestibular primary afferents with bulbs in apparent contact with vestibulospinal neurons were transneuronally labeled by biocytin. They were observed in the ipsilateral aVIIIn and the contralateral pVIIIn and could be followed in the labyrinths, where they innervated the vertical and horizontal arms of the semicircular canal crests. Taken together, these results indicate that vestibular primary afferents from the aVIIIn innervate predominantly vestibulospinal neurons of the intermediate octavomotor nucleus, whereas afferents from the pVIIIn innervate vestibulospinal neurons in the posterior octavomotor nucleus. This anatomical organization suggests that afferents carrying bulbs convey dynamic information to vestibulospinal neurons, which, in turn, project to the spinal cord networks.
利用解剖示踪剂，对七鳃鳗前庭初级传入神经的分布及其与前庭脊髓和其他脑干神经元的关系进行了研究。前庭神经前支（aVIIIn）和后支（pVIIIn）的传入神经主要位于八分体外侧区的腹侧核。通过将一种荧光示踪剂应用于整个前庭神经或其一个分支，并将另一种示踪剂应用于脊髓，研究了传入神经与前庭脊髓神经元之间的关系。一些传入神经显示出大的、球状的膨大（球状体），在前八分体运动核和中间八分体运动核中发现了约20个这样的球状体，而在后八分体运动核中发现了约40个。一些球状体与中间八分体运动核中的前庭脊髓神经元有明显接触，且大多起源于aVIIIn，而后八分体运动核中的球状体起源于pVIIIn。将生物胞素应用于延髓脊髓半节段，标记了位于同侧中间八分体运动核和对侧后八分体运动核的前庭脊髓神经元。此外，与前庭脊髓神经元有明显接触的带有球状体的前庭初级传入神经被生物胞素跨神经元标记。它们在同侧aVIIIn和对侧pVIIIn中被观察到，并可在迷路中追踪到，在那里它们支配半规管嵴的垂直和水平臂。综上所述，这些结果表明，来自aVIIIn的前庭初级传入神经主要支配中间八分体运动核的前庭脊髓神经元，而来自pVIIIn的传入神经支配后八分体运动核的前庭脊髓神经元。这种解剖学组织表明，携带球状体的传入神经向前庭脊髓神经元传递动态信息，而前庭脊髓神经元又投射到脊髓网络。
