Central Neuronal Activity in Vestibular Compensation

描述（由申请人提供）：本项目旨在阐明灵长类动物前庭损伤（前庭代偿）恢复的机制。实验重点探讨单侧迷路切除或半规管封堵后前庭眼反射恢复的生理过程。该研究将考虑在被动和主动头部运动时前庭反应的补偿。对于被动头部运动，前庭代偿已被发现是不完整的。通过前庭外周病变前后双侧前庭核吻侧的细胞外单单位记录，研究了平移和旋转运动反射补偿的神经元底物。关于动态前庭反射补偿的中心机制的假设将直接测试。这些假设包括前庭联合系统可塑性的作用，耳石-眼系统的永久性缺陷是编码平移和重力信息的中枢神经元线性加速度敏感性永久性重新定向的结果。对于主动的头部运动，初步研究通过分析迷路损伤后不受约束的眼和头扫视运动（无头注视转移），探讨了意志在头部运动时眼部代偿反应中的作用。这些研究表明，受试者能够利用编码头部运动和/或颈部或视觉反馈的神经信号副本来促进自然，不受约束的头部运动中的行为补偿。本研究还将验证一种假设，即在这些头部运动中，编码意志性头部运动的神经信号副本被用来修改这些前庭中枢神经元的反应，从而促进补偿动物在旋转运动期间凝视的稳定。这项研究是p.l.的成果。他对前庭代偿的兴趣源于他以前的研究经验和他作为耳鼻喉科医生治疗抱怨头晕的病人的工作。

DESCRIPTION (provided by applicant): The purpose of this project is to elucidate the mechanisms involved in recovery from vestibular injury (vestibular compensation) in primates. Experiments focus on the physiological processes underlying recovery of the vestibulo-ocular reflex following unilateral labyrinthectomy or plugging of the semicircular canals. The study will consider compensation of vestibular response during both passive and active head movements. For passive head movements, vestibular compensation has been found to be incomplete. The neuronal substrate for compensation of reflexes to both translational and rotational movement will be investigated using extracellular single unit recordings from the rostral bilateral vestibular nuclei both before and after peripheral vestibular lesion. Hypotheses concerning the central mechanisms of compensation of dynamic vestibular reflexes will be directly tested. These hypotheses include a role for plasticity in the vestibular commissural system and that permanent deficits in the otolith-ocular system are a result of permanent reorientation of the linear acceleration sensitivities of central neurons that encode translational and gravity information. For active head movements, preliminary studies have investigated the role played by volition in compensatory ocular responses during head movement by analyzing unrestrained eye and head saccadic movements (head-free gaze shifts) after labyrinthine lesion. These studies suggested that a subject is able to utilize copies of neural signals that encode head movements and/or cervical or visual feedback to facilitate behavioral compensation during natural, unrestrained head movements. This study will also test the hypothesis that copies of neural signals encoding volitional head movements are used during those head movements to modify the response of these central vestibular neurons, facilitating the stabilization of gaze during rotational movements in compensated animals. This research is an outgrowth of the P.l.'s interest in vestibular compensation developed from his previous research experience and from his work as an otolaryngologist treating patients complaining of dizziness.