Effects of altered input from the neck on upper limb sensorimotor integration

我们中的大多数人都有过伸手去拿某个物体并找不到的经历，或者有过在电脑上比平时更多地打字的经历。我们可能没有考虑到的是，这些体验可能是由于我们脖子上感觉输入的改变而导致的感觉运动整合(SMI)改变的结果。SMI是中枢神经系统(CNS)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。在学习新技能以及在家里和工作场所执行任务时，有效的SMI是必不可少的。然而，我们对颈部感觉输入的改变如何影响上肢的SMI，以及这如何影响大脑对运动的控制以及我们如何学习新动作，知之甚少。最近，我的实验室发现，颈部肌肉疲劳削弱了我们在3D空间中准确知道手臂位置的能力。我们还发现，由于疼痛或僵硬而导致颈部输入长期变化的个体，在学习新的运动技能方面表现较差，空间意识也较差。我们认为这是因为来自颈部的感觉输入的变化干扰了我们的身体模式(一种提供我们身体各部分相互关系的位置的地图)。准确的身体模式对于产生准确和协调的动作至关重要。大脑的一部分，称为小脑，对于眼手协调和适应我们身体的位置和运动非常重要，以保持我们身体模式的正确表示，当我们环视周围时，我们不断变化的视觉体验。我的研究表明，颈部输入的改变正在影响小脑的工作方式。 我正在研究改变颈部的感觉输入，使用颈部肌肉疲劳和笨拙的姿势，如何影响来自手臂的SMI，以及如何影响对手臂肌肉的运动指令。我们还在研究小脑如何整合眼睛和手的运动。 在工作场所，有许多常见的任务需要在颈部处于笨拙的姿势或容易疲劳时进行精确的上肢运动，例如机械师或流水线工人的高空工作，或者外科医生、牙医和卫生员的精密工作。在日常生活中，我们利用身体模式在驾驶、进行熟练运动或与科技互动时准确地获得控制。在这些任务中，经常会出现颈部疲劳和/或颈部姿势改变。如果改变颈部输入影响上肢功能的速度和准确性，就有可能导致错误，从而影响加拿大工人的健康和生产力。从这项工作中获得的知识将提高我们对颈部疲劳和姿势变化如何影响工作、运动和休闲中的运动技能训练和表现的理解。在我们的技术时代，这项工作具有巨大的潜力来改进工作场所和技术设计的策略，以降低受伤风险和提高绩效。

Most of us have had the experience of reaching for an object and missing, or had days when we make more typos than usual while on our computers. What we may not have considered is that these experiences may be the consequences of altered sensorimotor integration (SMI) due to altered sensory input from our necks. SMI is the ability of the central nervous system (CNS) 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. Yet we understand very little about how changing the sensory input from the neck impacts SMI of the upper limb, and this affects the brain’s control of movement and how we learn new actions. Recently my lab has found that neck muscle fatigue impairs our ability to know exactly where our arm is located in 3D space. We have also found that individuals with chronic changes in neck input due to pain or stiffness are worse at learning new movement skills and have worse spatial awareness. We think this is because changes in sensory input from the neck interferes with our body schema (a map providing awareness of the position of our body parts in relation to one another). An accurate body schema is critical for producing accurate and coordinated movement. Part of the brain called the cerebellum is really important for eye-hand coordination and adapting the position and movements of our body to maintain the correct representation of our body schema with respect to our changing visual experience as we look around. My work suggests that the altered neck input is affecting the way the cerebellum does its job. I am studying how changing sensory input from the neck, using neck muscle fatigue and awkward postures, affects SMI from the arm and how this affects the motor commands to the arm muscles. We are also looking at how the cerebellum integrates eye and hand movements. There are a number of common tasks in workplaces 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, playing skilled sport or interacting with technology. Neck fatigue and/or altered neck postures are often present during these tasks. If altered neck input impacts the speed and accuracy of upper limb performance, it has the potential to lead to errors which impact the health and productivity of Canadian workers. The knowledge gained from this work will improve our understanding how neck fatigue and altered postures impact motor skill training and performance at work, sport and leisure. In our age of technology, this work has great potential to improve strategies for workplace and technology design to decrease injury risk and improve performance.