SENSORY-MOTOR/ADAPTIVE MECHANISMS IN EQUILIBRIUM CONTROL

控制老年人的平衡是一项重要的公共卫生 这是因为随着年龄的增长，两者的发病率都在增加。 头晕和福尔斯。 前庭系统对于维持 通过各种姿势和定向反射保持平衡。 之一 它的主要功能是前庭眼反射（VOR）， 在头部运动期间眼睛的补偿旋转，以便 保持眼睛对视觉目标的注视，因此稳定的视网膜 形象 VOR由两种头部运动激活：角度（ AVOR），由半规管驱动，和线性（LVOR），由 耳石 VOR的一个重要特征是它能够自适应地 改善对长时间视觉-前庭不匹配的反应性能 在头部运动中。 此外，最近的证据表明， VOR还受到瞬时观测条件（例如，目标 距离和凝视），在LVOR中比在AVOR中更是如此。 这个项目 重点放在VOR上，因为它是最直接和最易访问的行为 由此可以得出关于前庭功能的机械推论。 LVOR通常比AVOR受到较少的关注。 自适应 可塑性仅在AVOR中得到证实，尚未得到探索 在LVOR。 对老化的研究也仅限于AVOR。 在 在过去的支持期内，发现了随年龄增长的渐进性恶化 在AVOR及其适应能力，特别是当强调高 头速度和频率。 我们现在把注意力转向人类 LVOR，其与AVOR和视觉跟随的关系，以及新颖性 不同年龄组的适应机制。 新技术将 研究这些功能，以确定其基本功能。 性能和塑料特性。 我们还将强调LVOR， 视觉驱动的自适应机制，以揭示局限性， 随着年龄的增长而恶化。 我们假设LVOR将更大 老化敏感性高于AVOR，认为两者综合研究 VOR将使我们能够推断出根本利益的机制， 与年龄依赖性不平衡相关的潜在头晕和 福尔斯。

The control of equilibrium in the elderly is an important public health concern because aging is accompanied by an increasing incidence of both dizziness and falls. The vestibular system is crucial in maintaining equilibrium through a variety of postural and orienting reflexes. One of its major functions is the vestibulo-ocular reflex (VOR), which generates compensatory rotations of the eyes during head movements in order to maintain ocular fixation on visual targets, and therefore a stable retinal image. The VOR is activated by two kinds of head motion; angular (the AVOR), driven by the semicircular canals, and linear (the LVOR), driven by the otoliths. An important feature of the VOR is its ability to adaptively modify performance in response to prolonged visual-vestibular mismatch during head movements. In addition, recent evidence has demonstrated that the VOR is also modulated by instantaneous viewing conditions (e.g. target distance and gaze), more so in the LVOR than the AVOR. This project focuses on the VOR because it is the most direct and accessible behavior from which mechanistic inferences about vestibular function can be derived. The LVOR has generally received less attention than the AVOR. Adaptive plasticity has only been demonstrated in the AVOR, and remains unexplored in the LVOR. Studies on aging have also been limited to the AVOR. In the past support period, progressive age-dependent deterioration was uncovered in the AVOR and its adaptive capabilities, especially when stressed by high head velocities and frequencies. We now turn our attention to the human LVOR, its relationship with the AVOR and with visual following, and novel adaptive mechanisms in different age groups. New techniques will be employed to study these functions in order to define their basic performance and plastic characteristics. We will also stress the LVOR and visually-driven adaptive mechanisms to uncover limitations and deteriorations with aging. We hypothesize that the LVOR will be more sensitive to aging than the AVOR, and that a comprehensive study of both VORs will allow us to infer mechanisms of fundamental interest as well as those relevant to age-dependent disequilibrium underlying dizziness and falls.