Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, NC, 27599, USA.
Sci Rep. 2017 Oct 24;7(1):13960. doi: 10.1038/s41598-017-14555-x.
The extensor digitorum communis (EDC) is a multi-compartment muscle that allows dexterous extension of the four digits. However, the level of common input shared across different compartments of this muscle is not well understood. We seek to systematically characterize the common and independent neural input, originated from different levels of the central nervous system, to the different compartments. A motor unit (MU) coherence analysis was used to capture the different sources of common and independent input, by quantifying the coherence of MU discharge between different compartments. The MU activities were obtained from decomposition of surface electromyogram recordings. Our results showed that the MU coherence across different muscle compartments accounted for only a small proportion (<20%) of the total input in the alpha (5-12 Hz) and beta (15-30 Hz) bands, but was a major driver (>60%) in the delta (1-4 Hz) band. Additionally, cross-compartment coherence between the middle and ring-little fingers tended to be higher as compared with other finger combinations. Overall, the common input shared across different fingers are found to be at low to moderate levels, in comparison with the total input, which allows dexterous control of individual digits with some degree of coordinated control of multiple digits.
伸指总肌（EDC）是一块多肌腔肌，能够灵活地伸展四个手指。然而，对于这块肌肉的不同肌腔之间共同输入的程度还不是很清楚。我们试图系统地描述共同的和独立的神经输入，这些输入源于中枢神经系统的不同水平，作用于不同的肌腔。通过量化不同肌腔之间的运动单位（MU）放电的相干性，运动单位相干性分析用于捕捉共同和独立输入的不同来源。MU 活动是从表面肌电图记录的分解中获得的。我们的研究结果表明，不同肌腔之间的 MU 相干性仅占 alpha（5-12 Hz）和 beta（15-30 Hz）频段总输入的一小部分（<20%），但在 delta（1-4 Hz）频段是主要驱动力（>60%）。此外，中指和环指与小指之间的肌腔间相干性与其他手指组合相比往往更高。总的来说，与总输入相比，不同手指之间的共同输入被发现处于低到中等水平，这使得单个手指能够灵活控制，并且多个手指可以在一定程度上协调控制。
