Probing an increased reliance on reticulospinal motor pathways in chronic hemiparetic stroke with advanced spinal cord functional MRI

项目摘要/摘要 慢性偏瘫中风患者通常有严重的上肢运动障碍。这些 损害包括“关联反应”和异常的“肌肉协同作用”，其特征是 四肢肌肉的协同激活模式。据推测，这些运动障碍是由于 中风后对侧皮质网状脊髓束(CRST)的上调 皮质醇通路。大脑中的神经成像，包括功能磁共振成像(FMRI)和 肌电(EMG)研究已经广泛证实了这一假设，同时也留下了明显的差距 在皮质神经功能和骨骼肌协同激活模式的测量之间。据我们所知， 在中风后运动障碍的背景下，脊髓中的神经活动还没有被研究。 因此，将先进的人类脊髓功能磁共振成像方法与肌电技术相结合是至关重要的。 调查慢性偏瘫卒中患者对CRST的依赖程度。 本研究的目的是研究卒中后运动的神经机制。 为制定更有针对性的治疗干预措施提供信息。如果上调了 CRST负责偏瘫上肢的力量产生，其特点是双侧和双侧 当激活非偏瘫的手时，单侧投射预计会引发相关的反应，并且 当激活瘫痪的手时，瘫痪肢体的肌肉协同作用。脊髓功能磁共振成像可以提供直接的洞察力 神经激活和运动通路在人类颈髓中的应用。在拟议的项目中， 参与者将执行单侧等长握手任务；肌肉活动将通过肌电进行测量 脊髓神经活动将通过功能磁共振成像进行测量。目标1将调查关联的 脊髓神经活动的反应和偏侧化。CRST驱动的相关反应预计将 在手术时引起肢体间肌肉协同激活和双侧脊髓神经激活增加 用非轻瘫的手完成任务。目的2探讨异常运动协同效应与运动功能异常的关系。 运动激活的纵向范围。由分散的单边CRST预测推动的协同效应预计将 导致肢体内肌肉协同激活增加，脊髓纵向激活程度增加。 为了执行这项研究项目，申请者将获得中风的神经病理生理学和 EMG，接受神经科学和磁共振成像专家的指导，并培训科学 沟通、指导和领导力。西北大学的合作医学校园，与 神经成像专家和最先进的研究专用核磁共振扫描仪，为 科学培训和创新研究。先进的脊髓功能磁共振成像技术的新实现 将有助于我们理解和治疗慢性偏瘫卒中的刻板印象的运动模式。

PROJECT SUMMARY/ABSTRACT Individuals with chronic hemiparetic stroke typically have significant upper extremity motor impairments. These impairments include “associated reactions” and abnormal “muscle synergies”, characterized by inter- and intra- limb muscle coactivation patterns, respectively. It has been postulated that these motor impairments are due to an upregulation of the contralesional cortico-reticulospinal tract (CRST), after stroke-inflicted damage to corticofugal pathways. Neuroimaging in the brain, including functional magnetic resonance imaging (fMRI) and electromyography (EMG) studies, have widely substantiated this hypothesis, while leaving a tangible gap between measures of cortical neural function and skeletal muscle coactivation patterns. To our knowledge, neural activity in the spinal cord has not been investigated in the context of post-stroke motor impairments. Therefore, it is critical to integrate advanced fMRI methods in the human spinal cord with EMG techniques to investigate an increased reliance on the CRST in chronic hemiparetic stroke. The objectives of this research proposal are to investigate the neural mechanisms of post-stroke motor impairment and long-term to inform development of more targeted therapeutic interventions. If upregulation of the CRST is responsible for force generation in the paretic upper extremity, its characteristic bilateral and unilateral projections would be expected to drive associated reactions when activating the non-paretic hand, and muscle synergies in the paretic limb when activating the paretic hand. Spinal cord fMRI can provide direct insight into neural activation and motor pathway use in the human cervical spinal cord. In the proposed project, participants will perform unilateral isometric hand-grasping tasks; muscle activation will be measured with EMG and spinal cord neural activity will be measured with fMRI. Aim 1 will investigate the relationship of associated reactions and the lateralization of spinal cord neural activity. CRST-driven associated reactions are expected to elicit increased inter-limb muscle coactivation and more bilateral spinal cord neural activation when performing the task with the non-paretic hand. Aim 2 will investigate the relationship of abnormal motor synergies and the longitudinal extent of motor activation. Synergies driven by diffuse unilateral CRST projections are expected to elicit increased intra-limb muscle coactivation and an increased longitudinal extent of spinal cord activation. To execute this research project, the applicant will gain expertise in the neuropathophysiology of stroke and EMG, receive mentorship from experts in neuroscience and magnetic resonance imaging, and train in scientific communication, mentorship, and leadership. Northwestern University’s collaborative medical campus, with neuroimaging experts and state-of-the art research-dedicated MRI scanners, fosters a complete environment for scientific training and innovative research. The novel implementation of advanced spinal cord fMRI techniques will inform our understanding and treatment of stereotypical movement patterns in chronic hemiparetic stroke.