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。实验将集中在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。通过分析迷路损伤前后的自由眼球和头部跳视运动(无头部凝视移动)，研究意志在头部运动过程中的代偿性眼球反应中所起的作用。在单侧迷路损伤前和代偿后，将分析前庭核团神经元的单个单位记录的变化，以了解其动眼运动和角加速度敏感性的变化。需要测试的假设是：(1)前庭-眼睛反应中出现的被动前庭代偿是双侧前庭核团之间连合连接可塑性的结果；(2)代偿动物前庭核团中的神经元具有与完整动物相同的动眼敏感性；(3)动物能够利用神经信号的传出副本来编码头部运动和/或颈部反馈，以促进在自然、自由的头部运动中的行为补偿。这项研究是应聘者对前庭补偿感兴趣的结果，这源于他之前的研究经验，以及他作为耳鼻喉科医生治疗患者头晕的工作。这项提案中的工作将在W.迈克尔·金博士的指导下，与密西西比大学医学中心研究前庭和眼球运动功能的不同研究人员合作完成。为了补充实验室的工作，候选人将接受计算机功能和编程以及生物统计学的指导，以帮助候选人成为研究前庭系统可塑性的独立调查员/临床医生，特别是与自然头部运动有关的可塑性。

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.