Investigating resting-state BOLD fMRI in the human spinal cord as a means to improve imaging methods and understanding of spinal cord physiology

研究人类脊髓的静息态 BOLD fMRI，作为改进成像方法和了解脊髓生理学的一种手段

• 批准号: RGPIN-2015-06221
• 负责人: Stroman, Patrick
• 金额: $ 2.4万
• 依托单位: Queen's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=614017
• 关键词: Investigating; resting; state; BOLD; fMRI

Regulation of the excitability of spinal cord neurons by higher structures in the brainstem has been studied extensively and is an important component of sensory and pain perception. It is also important for quantitative MRI methods because this regulation may produce an unknown source of signal variance in time, even in the absence of a stimulus. Moreover, this descending regulation, and whether it is active and continuous, or entirely reactive to sensory or proprioceptive input, is important to our understanding of normal spinal cord function. Resting-state functional magnetic resonance imaging (fMRI) studies in the brain have proven to be extremely valuable for our understanding of cortical function, and there is now evidence for resting-state blood oxygenation-level dependent (BOLD) fluctuations in the cord and brainstem as well. The proposed research is part of a larger research program, and aims to answer two key questions: Are the apparent resting-state BOLD fluctuations in the spinal cord related to physiological motion, or natural fluctuations in blood gases during the respiratory cycle? Do the resting-state fluctuations change during sensory, motor, or cognitive stimulation? The answers to these questions will confirm whether or not there are continual natural variations in neural activity in the spinal cord, thereby improving our understanding of spinal cord function. Determining the contributions (if any) from physiological motion and variations during respiration will help to improve the sensitivity of quantitative MRI methods in the spinal cord.   The proposed research builds upon my years of work to develop functional MRI methods for the brainstem and spinal cord. This work includes developing optimal imaging methods, writing dedicated analysis software, and characterizing sources of noise (i.e. unidentified or unpredictable signal variance) and artifacts in MR images of the spinal cord. Because of this prior work and experience, I am in a unique position to carry out the proposed research. The innovative approach I will take is to isolate the various contributions to MRI signal variance based on their origins and temporal properties as determined in previous studies, and identify the BOLD contribution. How the BOLD contribution varies with MR data acquisition parameters, and with motor, sensory, and cognitive functions, will demonstrate its origin(s).   The proposed research presents valuable training opportunities for graduate students and research assistants, and continues my long record of training highly successful students. The skills and experience gained will contribute to a deep understanding of fMRI methods and the underlying theory, as well as understanding of spinal cord and brainstem neurophysiology. More importantly, it will provide valuable broader experience of multi-disciplinary research that can be carried into a wide range of future career paths.

脑干中的高级结构对脊髓神经元兴奋性的调节已被广泛研究，并且是感觉和疼痛感知的重要组成部分。这对定量MRI方法也很重要，因为即使在没有刺激的情况下，这种调节也可能产生未知的信号方差源。此外，这种下行调节，以及它是否是主动和持续的，或完全反应于感觉或本体感受输入，对我们理解正常脊髓功能很重要。静息态脑功能磁共振成像（fMRI）研究已被证明是非常有价值的，为我们的皮质功能的理解，现在有证据表明，静息态血氧水平依赖（BOLD）波动在脊髓和脑干。这项研究是一个更大的研究计划的一部分，旨在回答两个关键问题：脊髓中明显的静息状态BOLD波动是否与生理运动有关，或者呼吸周期中血气的自然波动？在感觉、运动或认知刺激过程中，静息状态的波动会改变吗？这些问题的答案将证实脊髓神经活动是否存在持续的自然变化，从而提高我们对脊髓功能的理解。确定呼吸过程中生理运动和变化的贡献（如果有的话）将有助于提高脊髓定量MRI方法的灵敏度。 这项拟议中的研究建立在我多年来为脑干和脊髓开发功能性MRI方法的工作基础上。这项工作包括开发最佳的成像方法，编写专用的分析软件，并表征脊髓MR图像中的噪声源（即未识别或不可预测的信号方差）和伪影。由于之前的工作和经验，我处于独特的地位来开展拟议的研究。我将采取的创新方法是根据先前研究中确定的起源和时间特性来隔离对MRI信号方差的各种贡献，并确定BOLD贡献。BOLD贡献如何随MR数据采集参数以及运动、感觉和认知功能而变化，将展示其起源。 拟议中的研究为研究生和研究助理提供了宝贵的培训机会，并延续了我长期以来培养非常成功的学生的记录。所获得的技能和经验将有助于对功能磁共振成像方法和基本理论的深入理解，以及对脊髓和脑干神经生理学的理解。更重要的是，它将提供多学科研究的宝贵经验，这些经验可以用于未来的职业道路。