Function of Vestibular-Nerve Afferent Types

描述(申请人提供)：前庭系统负责收集有关头部在空间中的位置和运动的信息。这些信息被用来通过前庭脊髓反射的动作来保持姿势，并通过前庭眼睛反射(VOR)来稳定凝视。由于前庭对脑干的输入中断，这些反射功能障碍可导致梅尼埃病和氨基糖苷类毒性等病理，并可能导致致残性眩晕和平衡失调。在哺乳动物中，有三种类型的前庭神经传入神经元将这些信号从前庭外周传递到脑干，但这些不同类别的目的尚不清楚。根据它们的灵敏度和基线放电模式，它们被称为“规则放电”、“非规则放电”和“低增益非规则放电”。 间接证据表明，这些传入类型可能受到不同病理过程的不同影响。本研究旨在通过可逆地刺激或抑制不规则传入在高频正弦旋转和短暂的头部瞬间运动中对前庭-眼反射的贡献，来确定不规则传入对VOR的贡献。非正规传入神经的动态变化表明，在这些以前未经检验的条件下，它们对VOR的贡献可能特别重要。将使用信号论技术，基于单个传入对剧烈运动的反应，确定在VOR允许的短潜伏期(&lt；10ms)内神经元的相对信息承载能力。将从收集的数据中开发出一个前庭神经传入模型，用于预测对高频和瞬时头部运动的神经反应。这项研究的发现将有助于更好地了解外周前庭系统的病理。

DESCRIPTION (provided by applicant): The vestibular system is responsible for collecting information about the head's position and movement in space. This information is used to maintain posture through the actions of the vestibulospinal reflexes and to stabilize gaze by means of the vestibulo-ocular reflex (VOR). Dysfunction of these reflexes due to disruption of vestibular input to the brainstem can lead to pathologies such as Meniere's disease and aminoglycoside toxicity and may bring about disabling vertigo and disequilibrium. In mammals, three types of vestibular-nerve afferent neurons carry these signals from the vestibular periphery to the brainstem, but the purpose for these separate classes is not known. Based on their sensitivity and baseline discharge patterns, they have been termed "regularly discharging," "irregularly discharging," and "low-gain irregularly discharging." Indirect evidence suggests that these afferent types may be differentially affected by various pathologic processes. The studies proposed here aim to define the contribution of irregular afferents to the VOR by reversibly stimulating or inhibiting their contribution to the vestibulo-ocular reflex during high-frequency sinusoidal rotations as well as short transient motions of the head. The dynamics of irregular afferents suggest that their contribution to the VOR may be particularly important under these previously untested conditions. Techniques of signal theory will be used, based on the responses of individual afferents to sharp movements, to determine the relative information carrying capacity of neurons over the short latencies (< 10 ms) allowed by the VOR. A model of vestibular-nerve afferents that predicts neural responses to high-frequency and transient head motion will be developed from the data collected. Findings from this study will allow better understanding of pathologies of the peripheral vestibular system.