STRUCTURE AND FUNCTION OF VESTIBULOCOLLIC NEURONS

总体目标是确定 前庭脊髓通路在头的产生和控制中的作用 在灵长类动物中稳定和运动。头的意义 通过我们改变注视方向的能力来观察稳定性， 在大多数活动中保持双眼固定，我们的能力， 检测自运动并自适应地对外部施加的头部/身体做出反应 扰动前庭系统和颈椎疾病 影响头部的稳定性，并可以显着改变病人的 愿意诱发自我运动，并可能导致正常的恐惧 活动尽管重要，但我们的理解仍然存在很大差距 基本的前庭脊髓机制我们认为前庭脊髓 通道代表了迷宫控制的不同通道 或偏向脑干和脊髓感觉和运动回路;招募 取决于头部运动的性质， 扰动，眼睛的瞬时运动和轨道位置， 以及头部/颈部在躯干上的方向;并且两个通道都在 自主注视控制拟议的研究将直接测试这些 假设外侧前庭脊髓束（LVST）的细胞是 建议研究的重点。有三个基本的 问题：他们在哪里投射，他们的目标是谁，信号做什么 他们携带。(l)在麻醉的瘫痪动物中， 上颈椎节段和支配颈椎的节段 将使用电气和自然识别胸交界处 耳道/耳石刺激并用生物胞素进行细胞内标记， 说明其脑干和脊柱内形态。(2)使用 细胞内技术，前庭靶向神经元， 参与前庭-颈部反射，例如特定的颈部/背部 耳神经元、脊髓本体神经元和小脑前神经元将被鉴定， 前庭和本体感受器的突触输入 评估，其体细胞-树突和轴突形态由 生物胞素标记。(3)在警觉、训练有素的猴子、慢性单位和眼睛中 运动（包括扭转和聚散）记录和电子 刺激技术将用于识别C1和C7投射 LVST细胞，并表征其放电施加角和线性 头部加速度和全身倾斜以及自主眼跟踪， 近视注视;不规则神经管的突触贡献， 耳石传入细胞的加速反应也将是 使用电生理学范例进行评估。

The overall goals are to define the structure and function of vestibulospinal pathways in the generation and control of head stabilization and movement in primate. The significance of head stabilization is seen by our ability to change gaze orientation and maintain binocular fixation during most activities, and our ability to detect self-motion and adaptively react to externally-imposed head/body perturbations. Disorders of the vestibular system and cervical spine affect head stability, and can dramatically alter the patient's willingness to induce self-motion and can lead to trepidation of normal activities. Despite the importance, wide gaps remain in our understanding of basic vestibulospinal mechanisms. We propose that the vestibulospinal pathways represent distinct channels through which the labyrinth controls or biases brainstem and spinal sensory and motor circuits; the recruitment of these channels depends upon the nature of the head motion or perturbation, the instantaneous movement and orbital position of the eyes, and the orientation of the head/neck on trunk; and both channels are under voluntary gaze control. The proposed studies will directly test these hypotheses. Cells of the lateral vestibulospinal tract (LVST) are the principal focus of the proposed studies. There are three essential questions: where do they project, who do they target, and what signals do they carry. (l) In the esthetized, paralyzed animal LVST axons supplying the upper cervical segments and those innervating also the cervico- thoracic junction will be identified using electrical and natural canal/otolith stimulation and intracellularly labeled with biocytin to specify their brainstem and intraspinal morphology. (2) Using intracellular techniques, vestibular-target neurons that likely participate in vestibular-neck reflexes, e.g. specific neck/back otoneurons, propriospinal, and precerebellar neurons, will be identified, their synaptic input from vestibular and proprioceptive receptors assessed, and their soma-dendritic and axon morphology specified by biocytin labeling. (3) In the alert, trained monkey, chronic unit and eye movement (including torsion and vergence) recording and electrical stimulation techniques will be used to identify C1- and C7- projecting LVST cells, and characterize their discharge to imposed angular and linear head acceleration and whole body tilt and to voluntary ocular tracking and near viewing fixation; the synaptic contribution of irregular canal and otolith afferents to the cell's acceleration response also will be assessed using an electrophysiological paradigm.