Neural correlates of whole-body motion perception during balance perturbations in stroke survivors and their relationship to balance function

项目摘要/摘要 感觉和运动加工都在中风后受损，但经常单独研究，大多数 康复的重点是运动系统。我们目前对身体位置和感觉的理解 由于现有的方法主观、缺乏精确度和 在非功能性行为中，常被评估为上肢的单个关节。我的论文研究 使用机器人方法在感知和运动学习中理解本体感觉的贡献 神经生理学水平。学习与增强的本体感觉功能和改变 感觉运动神经生理学。虽然这些发现支持使用客观措施来 在学习的背景下量化本体感觉，并确定潜在的神经底物，神经 调节本体感觉对功能行为的贡献的机制，如平衡，尚不清楚。 当平衡被扰乱时，大脑必须整合多个关节和四肢的感觉输入才能感知 身体姿势，并计划适当的肌肉反应。我们实验室的发现表明中风 幸存者改变了大脑皮层的反应和肌肉的激活模式，以应对扰动，但事实并非如此 尚不清楚这些异常反应是否与全身运动知觉受损有关。 客观生物标志物，包括结构完整性和皮质对平衡扰动的反应 功能是必要的，以识别有跌倒风险的个人，并告知有针对性的 利用个体潜在的大脑平衡状态的干预措施。为了实现这一长期目标，我们 将在慢性中风幸存者(N=20)和神经典型老年人(N=20)中追求以下目标：1)测试 全身运动知觉差是否与平衡功能差有关；2)确定 在平衡扰动期间诱发的大脑皮层反应是根据 区分平衡扰动；以及3)测试感官结构完整性的测量 通路和皮层反应潜伏期与平衡功能有关。据我们所知，这是第一次 使用多模式方法识别躯体感觉背后的脑平衡关系的研究 功能性行为中的知觉。如果成功，这样的发现可能有助于改变现有的 康复干预将重点放在运动系统上，转向处理感觉的综合方法 以及对运动的感官贡献。鉴于跌倒的风险随着年龄的增长而增加，这将进一步增加 卒中后发展的躯体感觉和平衡功能的结构和功能生物标记物 是必要的，以确定有跌倒风险的个人，并促进有效的、以证据为基础的发展 康复干预。

PROJECT SUMMARY/ABSTRACT Both sensory and motor processing are impaired post-stroke, but frequently studied in isolation, with most rehabilitation focused on the motor system. Our current understanding of the perception of body position and movement (i.e. proprioception) is limited due to existing methodologies that are subjective, lack precision, and are often assessed in single joints of the upper limb during non-functional behaviors. My dissertation research used robotic methods to understand proprioceptive contributions to motor learning at a perceptual and neurophysiological level. Learning was associated with enhanced proprioceptive function and changes in sensorimotor neurophysiology. While these findings supported the value of using objective measures to quantify proprioception in the context of learning and identified underlying neural substrates, the neural mechanisms mediating proprioceptive contributions to functional behaviors, such as balance, is unknown. When balance is perturbed, the brain must integrate sensory input across multiple joints and limbs to perceive body position and plan the appropriate muscle response. Findings from our lab demonstrate that stroke survivors have altered cortical responses and muscle activation patterns in response to a perturbation, but it is unknown whether these abnormal responses are related to impairments in whole-body motion perception. Objective biomarkers, including structural integrity and cortical responses to balance perturbations, of balance function are necessary to identify individuals at risk for falls and to inform the development of targeted interventions that capitalize on an individual’s underlying brain-balance profile. Towards this long-term goal, we will pursue the following aims in chronic stroke survivors (N=20) and neurotypical older adults (N=20): 1) test whether worse whole-body motion perception is associated with worse balance function; 2) determine if cortical responses evoked during balance perturbations are modulating according to the difficulty of discriminating between balance perturbations; and 3) test whether measures of structural integrity in sensory pathways and cortical response latency are associated with balance function. To our knowledge, this is the first study using a multi-modal approach to identify brain-balance relationships underlying somatosensory perception during functional behaviors. If successful, such findings may contribute to a shift in existing rehabilitation interventions focused on the motor system towards integrative approaches that address sensory and perceptual contributions to movement. Given increased risk of falls with aging that is further increased post-stroke, developing structural and functional biomarkers of somatosensory perception and balance function is necessary to identify individuals at risk for falls, and to advance development of effective, evidence-based rehabilitation interventions.