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

项目总结/摘要 患有慢性轻偏瘫中风的个体通常具有显著的上肢运动障碍。这些 损伤包括“相关反应”和异常的“肌肉协同作用”，其特征在于肌间和肌内 肢体肌肉共激活模式，分别。据推测，这些运动障碍是由于 脑卒中后，皮质-网状脊髓束（CRST）表达上调， 离皮质通路脑神经成像，包括功能性磁共振成像（fMRI）和 肌电图（EMG）研究广泛证实了这一假设，同时留下了切实的差距 皮质神经功能和骨骼肌共激活模式之间的测量。据我们所知， 在中风后运动损伤的情况下，还没有研究脊髓中的神经活动。 因此，将先进的功能磁共振成像方法与肌电图技术结合起来， 研究慢性轻偏瘫卒中患者对CRST的依赖性增加。 本研究的目的是探讨脑卒中后运动的神经机制 因此，我们需要从长期和长期的角度来研究和制定更有针对性的治疗干预措施。如果上调 CRST负责麻痹上肢的力量产生，其特征性的双侧和 当激活非麻痹的手时，单侧投射预计会驱动相关的反应， 当激活麻痹的手时，麻痹肢体中的肌肉协同作用。脊髓功能磁共振成像可以提供直接的洞察力 人类颈髓的神经激活和运动通路。在拟议的项目中， 参与者将执行单侧等长抓握任务;肌肉激活将通过EMG测量 脊髓神经活动将用功能磁共振成像测量。目的1将研究相关的 反应和脊髓神经活动的偏侧化。预计CRST引起的相关反应 引起增加肢体间肌肉共激活和更多的双侧脊髓神经激活时， 用没有瘫痪的手来完成任务目的2将研究异常运动协同作用与 运动激活的纵向范围。由分散的单侧CRST预测驱动的协同作用预计将 引起增加的肢体内肌肉共激活和增加的脊髓激活的纵向范围。 为了执行这个研究项目，申请人将获得中风的神经病理生理学方面的专业知识， EMG，接受神经科学和磁共振成像专家的指导，并接受科学培训 沟通、指导和领导力。西北大学的合作医学校园，与 神经影像学专家和最先进的研究专用MRI扫描仪，培养了一个完整的环境， 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性中风的刻板运动模式。

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.