Department of Sensorimotor Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
Department of Physical Therapy, School of Health Sciences, Shinshu University, Nagano, Japan.
Neuroimage. 2020 Oct 15;220:117089. doi: 10.1016/j.neuroimage.2020.117089. Epub 2020 Jun 25.
Beta-band (15-30 Hz) corticomuscular and intermuscular coherences are important markers of the corticospinal interaction. The purpose of this study was to investigate whether amount of visual feedback during an isometric pinch grip contraction would influence these coherences in young and elderly adults. Thirty-three healthy young and elderly subjects performed pinch grip force-matching task with right thumb and index finger, while scalp electroencephalogram (EEG) and electromyogram (EMG) from the first dorsal interosseous (FDI) and abductor pollicis brevis (APB) muscles were recorded. The amount of visual feedback was altered by manipulation of visual gain (low and high). Beta-band corticomuscular coherence was computed between EEG over the sensorimotor cortex and EMG from the FDI muscle and between EEG and EMG from the APB muscle (EEG-FDI and EEG-APB coherences). Also, beta-band intermuscular coherence was computed between EMG signals from the FDI and APB muscles (EMG-EMG coherence). Task performance was quantified as standard deviation (SD) of force and mean force error (MFE). EEG-FDI coherence was larger at high than low visual gain in the elderly but not in the young subjects, whereas there was no effect of age or visual gain on EEG-APB coherence. EMG-EMG coherence was smaller at high than low visual gain in the young and elderly subjects. The MFE was smaller at high than low visual gain in the young and elderly subjects, but the SD of force was smaller at high than low visual gain only in the young subjects. These results suggest that the effect of aging on beta-band coherence depends on the amount of visual feedback and further that visual feedback modulates beta-band corticomuscular and intermuscular coherences differently.
β 波段（15-30Hz）皮质肌和肌间相干性是皮质脊髓相互作用的重要标志物。本研究旨在探讨在等长捏力收缩期间给予不同视觉反馈量是否会影响年轻和老年成年人的这些相干性。33 名健康的年轻和老年受试者使用右手拇指和食指进行捏力匹配任务，同时记录头皮脑电图（EEG）和第一背侧骨间肌（FDI）和拇指短展肌（APB）的肌电图（EMG）。通过操纵视觉增益（低和高）来改变视觉反馈量。计算了 FDI 肌肉的 EEG 与 EEG-FDI 相干性和 APB 肌肉的 EEG-APB 相干性之间的 EEG 与 FDI 肌肉之间的β 波段皮质肌相干性（EEG-FDI 和 EEG-APB 相干性）。还计算了 FDI 和 APB 肌肉之间的β 波段肌间相干性（EMG-EMG 相干性）。任务性能量化为力的标准差（SD）和平均力误差（MFE）。在老年人中，高视觉增益时 EEG-FDI 相干性大于低视觉增益，但在年轻受试者中则没有；而年龄或视觉增益对 EEG-APB 相干性没有影响。在年轻和老年受试者中，高视觉增益时 EMG-EMG 相干性小于低视觉增益。高视觉增益时 MFE 小于低视觉增益，但高视觉增益时力的 SD 仅在年轻受试者中小于低视觉增益。这些结果表明，β 波段相干性的老化效应取决于视觉反馈量，进一步表明视觉反馈对β 波段皮质肌和肌间相干性的调制方式不同。
