Stretch Reflex Contributions to Multijoint Coordination

牵张反射对多关节协调的贡献

• 批准号: 7019224
• 负责人: ERIC JON PERREAULT
• 金额: $ 26.25万
• 依托单位: REHABILITATION INSTITUTE OF CHICAGO D/B/A SHIRLEY RYAN ABILITYLAB
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-01 至 2010-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7019224
• 关键词: clinical research; joints; limbs; muscle; posture; reflex; stretch reflex

DESCRIPTION (provided by applicant): Abnormal interjoint coordination is a hallmark of neuropathologies such as stroke and spinal cord injury, and there is evidence that changes in stretch reflex function may contribute to this discoordination. Understanding the significance of these changes and how they might be reversed or reduced through rehabilitation is best done in the context of the unimpaired state. However, there is little information regarding the role of stretch reflexes in the unimpaired control of multijoint movement and posture. Rather, most human studies have focused on the stretch response to single joint perturbations, which allow for unambiguous regulation of muscle length, but do not address the complexities of real perturbations and real movements involving multiple muscles acting in multiple degrees of freedom. This purpose of this grant is to examine stretch reflex contributions to multijoint coordination in the unimpaired human arm. Specifically we will determine if the muscle activation patterns generated in response to whole limb perturbations arise from neurally-mediated, intermuscular (heteronymous) connections or if they simply represent the autogenic (homonymous) responses of individual muscles linked via the skeleton. In addition, the functional consequences of these actions will be addressed by quantifying the mechanical impact of any observed reflex actions. Our Aims are: 1) To examine the heteronymous reflexes connecting the elbow and shoulder by applying single joint perturbations to a single joint, and recording the changes in muscle activity elicited at both joints. These results will provide a "model-free" assessment of heteronymous linkages. 2) To examine the relative contributions of homonymous and heteronymous stretch reflex pathways in coordinating the response to whole limb perturbations. This will be investigated using a 3DOF robot to perturb limb posture and a 3D biomechanical model to estimate the resulting muscle length changes. Changes in muscle activation that are not directly linked to homonymous length changes are likely to represent the output of heteronymous pathways. 3) To examine the influence of reflexively evoked changes in muscle activity on the regulation of multijoint mechanics. The first two Aims are important for assessing the existence and connectivity of stretch reflex responses, but alone do not establish their functional consequences. The latter requires an assessment of how reflex responses influence the mechanical properties of a limb. This will be accomplished using nonlinear system identification techniques to estimate stretch reflex contributions to multijoint impedance. This study will be the first to investigate the role of multijoint stretch reflexes for coordinating arm posture in the 3DOF relevant to normal function. Our results will provide the essential basis for our further investigations into abnormal reflex function following stroke and will elucidate the degree to which spinal mechanisms should be targeted by rehabilitation interventions.

描述（由申请人提供）：关节间协调异常是中风和脊髓损伤等神经病理学的标志，有证据表明牵张反射功能的变化可能导致这种不协调。最好在未受损的状态下了解这些变化的重要性以及如何通过康复来逆转或减少这些变化。然而，关于牵张反射在多关节运动和姿势的不受损害的控制中的作用的信息很少。相反，大多数人类研究都集中在对单关节扰动的拉伸反应上，这允许对肌肉长度进行明确的调节，但没有解决涉及以多个自由度动作的多个肌肉的真实扰动和真实运动的复杂性。这笔拨款的目的是检查牵张反射对未受损的人类手臂多关节协调的贡献。具体来说，我们将确定响应整个肢体扰动而产生的肌肉激活模式是否源于神经介导的肌肉间（同名）连接，或者它们是否仅代表通过骨骼连接的各个肌肉的自生（同名）反应。此外，这些动作的功能后果将通过量化任何观察到的反射动作的机械影响来解决。我们的目标是： 1) 通过对单个关节施加单关节扰动，并记录两个关节引起的肌肉活动的变化，来检查连接肘部和肩部的同义反射。这些结果将为异名联系提供“无模型”评估。 2）检查同名和异名牵张反射通路在协调对整个肢体扰动的反应中的相对贡献。我们将使用 3DOF 机器人扰乱肢体姿势并使用 3D 生物力学模型来估计由此产生的肌肉长度变化来对此进行研究。与同名长度变化不直接相关的肌肉激活变化可能代表异名路径的输出。 3）考察肌肉活动反射性诱发变化对多关节力学调节的影响。前两个目标对于评估牵张反射反应的存在和连通性很重要，但单独并不能确定其功能后果。后者需要评估反射反应如何影响肢体的机械特性。这将通过使用非线性系统识别技术来估计牵张反射对多关节阻抗的贡献来完成。这项研究将首次研究多关节牵张反射在协调与正常功能相关的 3DOF 中手臂姿势中的作用。我们的结果将为我们进一步研究中风后反射功能异常提供必要的基础，并将阐明康复干预措施应针对脊柱机制的程度。