Gravity Dependence of Otolith System Function

本提案的主要目标是确定重力如何影响功能发育 前庭耳石系统。已知，即使适度暴露在改变的重力条件下， 成年动物可以在解剖学、生理学和神经运动反应中产生与 前庭系统。此外，更有限的证据表明，暴露在微重力或 胚胎发育和新生儿发育过程中的超重力条件会产生深刻的变化。 前庭系统的结构和功能。该项目将比较耳石系统的形态、生理学、 以及从受精到孵化后成熟过程中的行为反应 要么是地球正常、自转1g，要么是不同级别的超重力。第一个目标是检查和 日本鸣禽耳石受体和黄斑传入神经分布和类型的比较 不同的重力条件。我们预测，细胞的数量和终末神经支配模式 根据发育过程中所经历的重力，传入神经元将按比例增加。 第二个目标将检查耳石传入的敏感性、空间调谐和动态反应。 在不同重力条件下发育的成熟鹌鹑。第三个目标将检查以下方面的影响 重力环境改变对前庭眼球屈曲和头部凝视稳定性的影响 在直线运动过程中的成熟的鹌鹑。我们假设凝视反射组件被调整为引导 凝视行为与发育过程中经历的重力-惯性加速度常数有关。这些 研究将首次提供关于重力的存在如何影响 感受器和初级传入细胞获得直线运动反应性，以及 直线运动时头部姿势的稳定性。这些信息将提供对以下机制的新见解 从前庭损伤中恢复，并可能导致前庭相关疾病或 精神创伤。

The primary objective of the present proposal is to determine how gravity affects the functional development of the vestibular otolith system. It is known that even moderate exposure to altered gravity conditions in adult animals can produce modifications in the anatomy, physiology, and neuromotor responses related to the vestibular system. In addition, more limited evidence shows that exposure to either microgravity or hypergravity conditions during embryogenesis and neonatal development can produce profound alterations in vestibular system structure and function. This project will compare otolith system morphology, physiology, and behavioral responses in quails that have developed from fertilization through post-hatch maturity in either Earth normal, rotational 1g, or different levels of hypergravity. The first aim is to examine and compare the distribution and type of otolith receptors and macula afferent innervation in quails raised in different gravity conditions. We predict that the number of cells and the terminal innervation patterns of afferents will increase proportionally dependent upon the force of gravity experienced during development. The second aim will examine the sensitivity, spatial tuning, and dynamic responses of otolith afferents in mature quails that have developed in different gravity conditions. The third aim will examine the effects of development in altered gravity environments upon the vestibuloocular refelex and head gaze stability in mature quails during linear motion. We hypothesize that the gaze reflex components are tuned to direct gaze behavior relative to the gravito-inertial acceleration constant experienced during development. These studies will for the first time provide basic information regarding how the presence of gravity affects the acquisition of linear motion responsiveness by receptors and primary afferents, as well as the formation of head postural stability during linear motion. This information will provide new insight into mechanisms for recovery from vestibular injury and could lead to new treatment regimens for vestibular related disease or trauma.