Biomechanics of the Semicircular Canals

描述（由申请人提供）：本研究的长期目标是量化三维半规管热力学对健康和人体状况的贡献。目前的研究包括三个方面：1)管状结石的生物力学及其与良性位置性眩晕（BPV）的关系；2)热性眼球震颤的生物力学和生物物理基础；3)丘/毛束微观力学的时空分布。第一个目标将详细介绍在挑衅性诊断测试和管道重新定位过程中实验诱导的管道结石条件下的生物力学和神经反应。第二个目标是将热性眼球震颤的传统起源——温度依赖的液体浮力和毛细胞/传入兴奋性——与局部热膨胀和Tran迷路压的影响分开。结果将解决不对称热量眼震的起源和低重力和超重力下的热量反应。这两个目标在理解、诊断和治疗特定前庭疾病方面具有直接的临床意义。第三个目标是解决微观力学在形成传递到脑干的神经密码方面的贡献。几项研究表明，位于感觉上皮不同区域的感觉毛细胞接受不同的机械输入。我们将直接测量丘丘和毛束运动的区域差异。研究毛细胞/毛束运动的可能作用的实验将包括在内。将确定传出前庭系统的激活以及内淋巴的电极化对毛束位移的影响。详细的数学模型将广泛用于解释结果和指导实验研究。实验模型将是牡蛎蟾蜍鱼，Opsanus tau。半规管的基本结构是古老的，在从鱼到人的脊椎动物中显示出惊人的相似性。这使得这些研究能够使用相对原始的物种来解决与人类感觉生理学和健康相关的重要问题。

DESCRIPTION (provided by applicant): The long-term objective of this research is to quantify the contributions of three-dimensional semicircular canal thermo-mechanics as it related to health and the human condition. Present work includes three specific aims: l) biomechanics of canalolithiasis and its relationship to benign positional vertigo (BPV), 2) biomechanical and biophysical substrates of caloric nystagmus and, 3) spatio-temporal distribution of cupula/hair-bundle micro mechanics. The first aim will detail biomechanical and neural responses under conditions of experimentally induced canalolithiasis during provocative diagnostic tests and during canalith repositioning procedures. The second aim will separate traditional origins of caloric nystagmus -- temperature-dependent fluid buoyancy and hair-cell/afferent excitability -- from the influence of local thermal expansion and Tran labyrinthine pressure. Results will address the origin of asymmetric caloric nystagmus and caloric responses under hypo- and hyper-gravity. Both of these aims have direct clinical relevance in understanding, diagnosing and treating specific vestibular disorders. The third aim addresses micro mechanical contributions in shaping the neural code transmitted to the brain stem. Several lines of investigation indicate that sensory hair cells located within various regions of the sensory epithelium receive differing mechanical inputs. We will directly measure regional differences in cupula and hair bundle motion. Experiments to investigate the possible role of hair cell/bundle motility will be included. The influence of activation of the efferent vestibular system and, separately, electrical polarization of the endolymph on hair bundle displacements will be determined. Detailed mathematical models will be used extensively to interpret results and direct the experimental studies. The experimental model will be the oyster toadfish, Opsanus tau. The fundamental structure of the semicircular canals is ancient and shows remarkable similarity across vertebrates ranging from fish to man. This enables the use of a relatively primitive species for these studies to address important issues relevant to sensory physiology and health in human.