Davis J L, Xue J, Peterson E H, Grant J W
Department of Engineering Science and Mechanics and School of Biomedical Engineering and Sciences, Virginia Tech, Blacksburg, VA 24061, USA.
J Vestib Res. 2007;17(4):145-62.
Finite element models of otoconial membrane (OM) were developed to investigate the effects of three geometric variables on static and modal response of the OM: (1) curvature of the macular surface, (2) spatial variation in thicknesses of three OM layers, and (3) shape of the macular perimeter. A geometrically accurate model of a turtle utricle was constructed from confocal images. Modifying values for each variable formed variants of this model: modeling the macula surface as flat, OM layer thicknesses as spatially invariant, and the macular perimeter as a rectangle. Static tests were performed on each modified OM model, and the results were compared to determine the effects of each geometric variable on static mechanical gain (deflection per unit acceleration). Results indicate that all three geometric variables affect the magnitude and directional properties of OM static mechanical gain. In addition, through modal analysis, we determined the natural frequencies and displacement modes of each model, which illustrate the effects of the three geometric variables on OM dynamics. This study indicates the importance of considering three-dimensional OM geometry when attempting to understand responses of the OM and, therefore, the modulation of hair cell signals to accelerations during head movements.
建立了耳石膜（OM）的有限元模型，以研究三个几何变量对OM静态和模态响应的影响：（1）黄斑表面的曲率，（2）OM三层厚度的空间变化，以及（3）黄斑周长的形状。根据共聚焦图像构建了几何精确的龟耳模型。通过修改每个变量的值形成该模型的变体：将黄斑表面建模为平坦的，OM层厚度在空间上不变，以及黄斑周长为矩形。对每个修改后的OM模型进行静态测试，并比较结果以确定每个几何变量对静态机械增益（单位加速度下的偏转）的影响。结果表明，所有三个几何变量都会影响OM静态机械增益的大小和方向特性。此外，通过模态分析，我们确定了每个模型的固有频率和位移模式，这说明了三个几何变量对OM动力学的影响。这项研究表明，在试图理解OM的响应以及因此在头部运动期间毛细胞信号对加速度的调制时，考虑三维OM几何形状的重要性。
