A single low-dimensional neural component of spinal motor neuron activity explains force generation across repetitive isometric tasks

IF 4.1 2区综合性期刊 Q1 MULTIDISCIPLINARY SCIENCES

iScience Pub Date : 2025-09-03 DOI:10.1016/j.isci.2025.113483

Hélio V. Cabral , J. Greig Inglis , Elmira Pourreza , Milena A. Dos Santos , Caterina Cosentino , David O’Reilly , Ioannis Delis , Francesco Negro

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Abstract

Low-dimensional control is thought to underlie spinal motor neuron activity, with low-frequency oscillations in common synaptic inputs serving as the primary determinant of muscle force production. Here, we used principal-component analysis and factor analysis to investigate the role of low-dimensional motor unit components in force production during repetitive isometric tasks with similar force profiles. In both individual and synergistic human muscles, the first motor unit component explained most of the variance in smoothed discharge rates and showed higher correlations with force oscillations than the second component. Additionally, the first component, but not the second, remained highly consistent across trials. A non-linear network-information framework further confirmed these findings, revealing high motor unit network density in the first component across all muscles. These results suggest that during isometric contractions, force oscillations are primarily driven by a single dominant shared synaptic input to spinal motor neuron activity.

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脊髓运动神经元活动的单一低维神经成分解释了重复性等距任务中的力产生

低维控制被认为是脊髓运动神经元活动的基础，共同突触输入中的低频振荡是肌肉力量产生的主要决定因素。在这里，我们使用主成分分析和因子分析来研究低维运动单元组件在具有相似力剖面的重复性等长任务中的力产生中的作用。在个体和协同的人体肌肉中，第一个运动单元成分解释了平滑放电率的大部分差异，并且与力振荡的相关性高于第二个成分。此外，第一个成分，而不是第二个成分，在试验中保持高度一致。非线性网络信息框架进一步证实了这些发现，揭示了所有肌肉中第一成分的高运动单元网络密度。这些结果表明，在等长收缩过程中，力振荡主要由脊髓运动神经元活动的单一显性共享突触输入驱动。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

iScience Multidisciplinary-Multidisciplinary

CiteScore

7.20

自引率

1.70%

发文量

1972

审稿时长

6 weeks

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