Where Is Your Arm? Variations in Proprioception Across Space and Tasks
Where Is Your Arm? Variations in Proprioception Across Space and Tasks
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DOI：
10.1152/jn.00494.2009
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发表时间：
2010-01-01
影响因子：
2.5
通讯作者：
Bastian, Amy J.
中科院分区：
文献类型：
--
作者：
Fuentes, Christina T.;Bastian, Amy J.
富恩特斯CT，巴斯蒂安AJ。你的手臂在哪里？本体感觉在空间和任务中的差异。《神经生理学杂志》103卷：164 - 171页，2010年。首次发表于2009年10月28日；doi:10.1152/jn.00494.2009。肢体位置感对于运动控制和与环境的交互至关重要。然而，我们对这一基本的本体感觉过程的理解是有限的。例如，对于手臂本体感觉的准确性知之甚少：它是否会随着手臂构型的变化而变化，因为一些外周感受器只有在关节朝着极限角度移动时才会起作用？这些变化在不同任务中是否一致？本体感觉能力是否会根据我们试图定位的部位（例如，指尖位置与肘关节角度）而改变？我们使用机器人外骨骼在三个任务中研究了14种手臂构型下的本体感觉，要求健康受试者：1）在被动运动后将指针与肘关节角度匹配，2）在被动运动后将指针与指尖位置匹配，3）主动将他们的肘关节角度与指针匹配。在所有三个任务中，受试者高估了更极限的关节位置；这可能是由于外周感觉信号使估计产生偏差，作为一种防止受伤的安全机制。我们还发现，当用于判断指尖位置时，肘关节角度的估计比直接报告时更精确，这表明大脑更容易获取肢体端点位置而非关节角度。最后，主动运动时肘关节角度估计的精度比被动运动时有所提高，这证实了运动指令的传出副本以及α - γ运动神经元的共同激活有助于本体感觉估计的研究结果。总之，我们揭示了正常本体感觉处理的基本方面，不仅证明了依赖于关节构型且与任务无关的可预测偏差，还证明了在整合跨关节信息时精度的提高。
Fuentes CT, Bastian AJ. Where is your arm? Variations in proprioception across space and tasks. J Neurophysiol 103: 164-171, 2010. First published October 28, 2009; doi:10.1152/jn.00494.2009. The sense of limb position is crucial for movement control and environmental interactions. Our understanding of this fundamental proprioceptive process, however, is limited. For example, little is known about the accuracy of arm proprioception: Does it vary with changes in arm configuration, since some peripheral receptors are engaged only when joints move toward extreme angles? Are these variations consistent across different tasks? Does proprioceptive ability change depending on what we try to localize (e. g., fingertip position vs. elbow angle)? We used a robot exoskeleton to study proprioception in 14 arm configurations across three tasks, asking healthy subjects to 1) match a pointer to elbow angles after passive movements, 2) match a pointer to fingertip positions after passive movements, and 3) actively match their elbow angle to a pointer. Across all three tasks, subjects overestimated more extreme joint positions; this may be due to peripheral sensory signals biasing estimates as a safety mechanism to prevent injury. We also found that elbow angle estimates were more precise when used to judge fingertip position versus directly reported, suggesting that the brain has better access to limb endpoint position than joint angles. Finally, precision of elbow angle estimates improved in active versus passive movements, corroborating work showing that efference copies of motor commands and alpha-gamma motor neuron coactivation contribute to proprioceptive estimates. In sum, we have uncovered fundamental aspects of normal proprioceptive processing, demonstrating not only predictable biases that are dependent on joint configuration and independent of task but also improved precision when integrating information across joints.