Effect of altered neck sensory feedback on brain plasticity and upper limb sensorimotor integration

感觉运动整合（SMI）是中枢神经系统整合来自身体不同部位的感觉信息并形成适当的运动输出到肌肉的能力。有效的SMI在学习新技能以及在家庭和工作场所执行任务时至关重要。在这个技术使用的时代，颈部疼痛和疲劳是非常普遍的，但我们对颈部感觉输入改变如何影响上肢重度认知障碍的了解有限。我的研究发现，颈部肌肉疲劳会削弱我们在3D空间中准确知道手臂位置的能力，使我们在学习新的运动技能时变得更糟，并改变大脑在学习这些技能时的适应方式。我们认为这是因为颈部感觉输入的变化干扰了我们的身体图式（一种提供我们身体部位相互关系的位置意识的地图）。小脑是一个大脑结构，对准确和协调的运动至关重要，并保持准确的身体图式。我的研究表明，颈部输入的改变会影响小脑的工作方式。在我提出的研究计划中，我正在使用一些新技术，其中一些是在我自己的实验室开发和验证的，来研究如何改变颈部感觉输入，使用颈部肌肉振动，影响来自手臂的重度精神分裂症；这是如何影响手臂肌肉的运动指令的；以及小脑如何整合眼球和手的运动。我使用的是虚拟现实技术（VR），参与者看着虚拟角色的手臂，就好像那是他们自己的手臂一样。在一系列实验中，虚拟角色手臂的大小和/或速度的视觉反馈将被微妙地改变，因此参与者必须依靠自己的身体图式来准确地执行瞄准任务。我预计在VR之前颈部肌肉的振动会导致更差的表现，因为颈部振动会扭曲身体图式的准确性。这项工作将大大促进我们对颈部改变的感觉输入如何影响上肢重度认知障碍的理解，以及对大脑运动控制的影响，以及我们如何学习新动作。此外，这些知识具有重要的现实生活意义。例如，有许多常见的工作任务需要精确的上肢运动，而颈部处于尴尬的姿势，或者容易疲劳，例如机械师或装配线工人的头顶工作；或者外科医生、牙医和卫生学家的精密工作。在日常生活中，我们利用身体图式来准确地控制驾驶，进行熟练的运动或与技术互动。在这些任务中经常出现颈部疲劳和/或颈部姿势改变。如果颈部输入的改变影响上肢动作的速度和准确性，就有可能导致影响加拿大工人健康和生产力的错误。这项研究可以改善工作场所和技术设计的策略，以减少伤害，提高工作和VR环境中的表现。

Sensorimotor integration (SMI) is the ability of the central nervous system to integrate sensory information from different body parts and formulate appropriate motor outputs to muscles. Effective SMI is essential when learning new skills and when performing tasks at home and in the workplace. In this age of technology use, neck pain and fatigue are very common, yet we have limited understanding about how altered neck sensory input impacts upper limb SMI. My work has found that neck muscle fatigue impairs our ability to know exactly where our arm is located in 3D space, makes us worse at learning new movement skills, and alters the way the brain adapts when learning those skills. We think this is because changes in neck sensory input interferes with our body schema (a map providing awareness of the position of our body parts in relation to one another). The cerebellum is a brain structure critical for accurate and coordinated movement, and maintaining an accurate body schema. My work suggests that altered neck input affects the way the cerebellum does its job. In my proposed research program, I am using novel techniques, some of them developed and validated in my own lab, to study how changing neck sensory input, using neck muscle vibration, affects SMI from the arm; how this affects motor commands to the arm muscles; and how the cerebellum integrates eye and hand movements. I am using virtual reality (VR), where the participant looks at an avatar's arm that appears as if it is their own arm. In a series of experiments, the visual feedback of the size and/or speed of the avatar's arm will be subtly altered so that participants have to rely on their own body schema to accurately perform an aiming task. I expect that neck muscle vibration prior to VR will lead to worse performance because the neck vibration will distort the accuracy of the body schema. This work will significantly advance our understanding of how altered sensory input from the neck impacts upper limb SMI, and the effect on the brain's control of movement, and how we learn new actions. Moreover, this knowledge has important real life implications. For instance, there are a number of common workplace tasks that require precise upper limb movements while the neck is in an awkward posture, or is susceptible to fatigue, such as overhead work by mechanics or assembly line workers; or precision work by surgeons, dentists, and hygienists. On a daily basis, we utilize the body schema to accurately reach for controls while driving, play skilled sport or interact with technology. Neck fatigue and/or altered neck postures are often present during these tasks. If altered neck input impacts speed and accuracy of upper limb performance, it has the potential to lead to errors which impact the health and productivity of Canadian workers. This research can lead to improved strategies for workplace and technology design to decrease injuries and improve performance at work and in VR environments.