VESTIBULAR NUCLEUS ACTIVITY IN VESTIBULAR COMPENSATION

本项目的目的是阐明灵长类动物前庭损伤（前庭代偿）恢复的机制。实验将关注单侧迷路切除或半规管堵塞后前庭眼反射（VOR）恢复的生理过程。我们将通过分析迷路损伤前后眼和头的无约束跳眼运动（无头注视转移）来研究意志在头部运动时眼部代偿反应中的作用。分析单侧迷路病变前和代偿后前庭神经核神经元的单单元记录，观察其动眼力和角加速度敏感性的变化。有待验证的假设是：(1)前庭-眼反应中的被动前庭代偿是双侧前庭核连接可塑性的结果；(2)代偿动物前庭神经核中发现的神经元与完整动物具有相同的动眼肌敏感性；(3)动物能够利用编码头部运动和/或颈部反馈的神经信号的差分拷贝来促进自然，不受约束的头部运动期间的行为补偿。这项研究是候选人对前庭代偿感兴趣的产物，这是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患者的工作中发展起来的。本提案中的工作将在W. Michael King博士的指导下完成，并与密西西比大学医学中心研究前庭和动眼肌功能的不同研究小组合作。为了补充实验室的工作，候选人将接受计算机功能、编程和生物统计学方面的指导，以促进候选人成为研究前庭系统可塑性的独立研究者/临床医生，特别是与自然头部运动有关的研究。

The purpose of this project is to elucidate the mechanisms involved in recovery from vestibular injury (vestibular compensation) in primates. Experiments will focus on the physiological processes underlying recovery of the vestibulo-ocular reflex (VOR) following unilateral labyrinthectomy or plugging of the semicircular canals. The role played by volition in compensatory ocular responses during head movement will be investigated by analyzing unrestrained eye and head saccadic movements (head-free gaze shifts) before and after labyrinthine lesion. Single-unit recordings of neurons in the vestibular nuclei will be analyzed for changes in their oculomotor and angular acceleration sensitivity before unilateral labyrinthine lesion and after compensation. The hypotheses to be tested are that (1) passive vestibular compensation seen in vestibulo-ocular responses is the result of plasticity in the commissural connections between the bilateral vestibular nuclei; (2) the neurons found in the vestibular nuclei of the compensated animal carry the same oculomotor sensitivity as in the intact animal; and (3) the animal is able to utilize efference copies of neural signals which encode head movements and/or cervical feedback to facilitate behavioral compensation during natural, unrestrained head movements. This research is an outgrowth of the candidate's interest in vestibular compensation, which developed from his previous research experience and from his work as an otolaryngologist treating patients complaining of dizziness. The work in this proposal will be done under the direction of Dr. W. Michael King in collaboration with a diverse group of investigators who study vestibular and oculomotor function at the University of Mississippi Medical Center. To complement the work in the lab, the candidate will undergo instruction in computer function and programming and biostatistics to facilitate establishment of the candidate as an independent investigator/clinician studying plasticity in the vestibular system, particularly as it pertains to natural head movements.