Vestibular Contributions to Estimated Head Motion and Orientation

描述(申请人提供)：由前庭迷路提供的有关头部运动和方向的信息受到几个特征的限制，但大脑仍然是ABL，在前庭刺激过程中产生相对准确的知觉和眼动反应。前庭系统必须处理的一个主要问题是神经处理的各个方面所固有的噪音。在这个提案中，我们将使用几种新的技术(包括非人类灵长类动物的前庭心理物理学，半规管传入的高频电刺激，以及前庭-眼反射(VOR)阈值和中央前庭噪声的测量)来研究噪声如何影响负责前庭介导的眼球运动和知觉反应的中央处理。更具体地说，我们提出了三个假设，我们将在三个特定的目标中进行测试，重点是大脑优化知觉和眼动反应的能力，尽管迷宫提供的信息有限。在前两个具体目标中，我们将通过在正常的管传入信号上叠加极高频电刺激管壶腹部神经来改变管传入信号上的噪声量。我们将研究管道旋转输入上的噪声如何影响知觉和眼动反应，并预测当噪声增加时，大脑中的速度存储积分器将变得不那么有效(目标1)，而将低频转换为倾斜的误解将被强化(目标2)。在具体目标3中，我们将通过用氨基糖苷类药物诱导不同程度的外周前庭功能减退，并基于在固定头部的点状靶点时眼速变化来测量VOR和前庭噪声的行为指标的变化，来研究外周前庭消融增加中央前庭噪声的假设。总之，这些实验将有助于回答关于前庭信息是如何集中处理的长期和基本的问题，这项工作不仅将提高对正常前庭生理学的理解，还可能有助于阐明外周和中央前庭系统紊乱时发生的异常知觉和眼动反应的机制。

DESCRIPTION (provided by applicant): The information about head motion and orientation provided by the vestibular labyrinth is constrained by several features, but the brain is still abl to generate relatively accurate perceptual and eye movement responses during vestibular stimulation. One major problem the vestibular system must deal with is the noise inherent in all aspects of neural processing. In this proposal we will use several novel techniques (including vestibular psychophysics in non-human primates, high-frequency electrical stimulation of semicircular canal afferents, and measures of the vestibulo-ocular reflex (VOR) threshold and central vestibular noise) to investigate how noise affects the central processing that is responsible for vestibular-mediated eye movement and perceptual responses. More specifically, we propose three hypotheses which we will test in three specific aims that focus on the brain's ability to optimize perceptual and eye movement responses despite the limitations in the information provided by the labyrinth. In the first two specific aims, we will vary the amount of noise on the canal afferent signals by using very high-frequency electrical stimulation of the canal ampullary nerves superimposed on the normal canal afferent cues. We will investigate how noise on the canal rotational inputs affects perceptual and eye movement responses, and predict that when the noise increases the velocity storage integrator in the brain will become less effective (aim 1) and that the misperception of low-frequency translation as tilt will be accentuated (aim 2). In specific aim 3, we will investigate the hypothesis that peripheral vestibular ablation increases central vestibular noise by inducing different degrees of peripheral vestibular hypofunction with aminoglycosides and measuring changes in the VOR and in a behavioral measure of vestibular noise, based on changes in the variance of eye velocity during fixation of a punctate target with the head stationary. In sum, these experiments will help answer longstanding and fundamental questions about how vestibular information is processed centrally, and this work will not only improve understanding of normal vestibular physiology but may also help elucidate the mechanisms responsible for the abnormal perceptual and eye movement responses that occur with disorders of the peripheral and central vestibular system.