Multisensory Integration and Human Postural Control

描述（由申请人提供）：本研究的长期目标是了解神经系统如何融合来自多个感觉系统的信息以控制直立姿势。自适应地选择和重新加权替代方向参考的能力被认为是患者和老年人群中姿势控制的关键因素。尽管多感觉重新加权的重要性，很少有人知道它是如何实现的。我们已经开发出一种新的实验范式，同时操纵两个感官输入（视觉和触觉），以探测多感觉整合的属性。与此同时，我们已经开发了一个独特的两步建模方法，使用时间序列技术和机械模型，以确定哪些特征的姿势摇摆可以：i）归因于估计或控制;和ii）区分不同的估计机制用于多感官重新加权。具体目标是： I.表征姿势摇摆的感觉耦合和重加权特性。三个实验将精确地定义感官形式（视觉和触觉）提供的信息，以及这些形式如何通过重新加权进行交互。我们假设：a）强速度耦合和弱位置耦合; B）在频率上均匀重新加权;以及c）取决于感觉输入的均方根（RMS）速度的重新加权; 二.表征多感觉重加权的动力学。神经系统在模态内和模态之间重新加权感觉信息的时间尺度并不为人所知。两个实验将通过以下方式研究重新加权动态：1）在试验中添加或删除感觉模态; 2）在试验中改变环境运动的幅度。我们假设重新加权是：i）一个相对缓慢的过程; ii）取决于新增加的感觉输入的幅度; 伊利诺伊州确定双侧前庭丧失（BVL）患者和健康受试者的估计和控制有何不同。目前尚不清楚前庭信息的丢失是否会影响估计和/或控制。在BVL和健康受试者的姿势摇摆的动态特性的差异进行比较，两个实验使用视觉和触摸输入和固定或摇摆参考的支持表面。我们的假设是，前庭功能的丧失影响估计的性质，而不是控制。 该建议的意义在于：1）增强BVL患者的康复; 2）开发一种机制模型，将潜在的生理子系统与姿势控制明确联系起来。未来的工作将解决其他患者群体与类似的技术，以确定他们的平衡赤字的基础。

DESCRIPTION (provided by applicant): The long-term goal of this research is to understand how the nervous system fuses information from multiple sensory systems for the control of upright stance. The ability to select and reweight alternative orientation references adaptively is considered a critical factor for postural control in patient and elderly populations. Despite the importance of multisensory reweighting, little is known about how it is achieved. We have developed a new experimental paradigm that simultaneously manipulates two sensory inputs (vision and touch) to probe the properties of multisensory integration. In parallel, we have developed a unique two-step modeling approach using time series techniques and mechanistic models to determine which characteristics of postural sway can: i) be attributed to estimation or control; and ii) distinguish different mechanisms of estimation used for multisensory reweighting. The specific aims are: I. To characterize sensory coupling and reweighting properties of postural sway. Three experiments will precisely define the information that sensory modalities (vision & touch) provide and how the modalities interact through reweighting. We hypothesize: a) strong velocity coupling and weak position coupling; b) uniform reweighting across frequency; and c) reweighting that is dependent upon the root mean square (RMS) velocity of sensory input; II. To characterize the dynamics of multisensory reweighting. The time scale over which the nervous system reweights sensory information within a modality and between modalities is not well known. Two experiments will investigate reweighting dynamics by: 1) adding or removing a sensory modality within a trial; 2) changing the amplitude of environmental motion within a trial. We hypothesize that reweighting is: i) a relatively slow process; and ii) dependent upon the amplitude of a newly added sensory input; and Ill. To determine how estimation and control differ in individuals with bilateral vestibular loss (BVL) and healthy subjects. It is not known whether the loss of vestibular information influences estimation and/or control. Differences in the dynamic characteristics of postural sway will be compared in BVL and healthy subjects with two experiments using visual and touch input and fixed or sway-referenced support surfaces. Our hypothesis is that the loss of vestibular function influences properties of estimation, rather than control. The implications of this proposal are: 1) to enhance rehabilitation of individuals with BVL; and 2) to develop a mechanistic model that will explicitly link underlying physiological subsystems to postural control. Future work will address other patient populations with similar techniques to determine the basis of their balance deficits.