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.

中文翻译：

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视觉反馈的放大以不同方式调节年轻人和老年人的皮质肌肉和肌肉间连贯性

Beta 波段 (15-30 Hz) 皮质肌和肌间连贯性是皮质脊髓相互作用的重要标志。本研究的目的是调查等距捏握收缩期间的视觉反馈量是否会影响年轻人和老年人的这些连贯性。33 名健康的年轻和老年受试者用右手拇指和食指进行捏握力匹配任务，而第一骨间背肌 (FDI) 和拇短展肌 (APB) 的头皮脑电图 (EEG) 和肌电图 (EMG)记录。通过操纵视觉增益（低和高）来改变视觉反馈的数量。Beta 波段皮质肌肉相干性计算在感觉运动皮层的 EEG 和 FDI 肌肉的 EMG 之间以及 EEG 和 APB 肌肉的 EMG 之间（EEG-FDI 和 EEG-APB 相干性）。此外，还计算了来自 FDI 和 APB 肌肉的 EMG 信号之间的 β 波段肌间相干性（EMG-EMG 相干性）。任务表现被量化为力的标准偏差 (SD) 和平均力误差 (MFE)。EEG-FDI 相干性在老年人中高于低视力增益时更大，但在年轻受试者中则不然，而年龄或视力增益对 EEG-APB 相干性没有影响。在年轻和老年受试者中，EMG-EMG 相干性在高视力增益时小于低视力增益。年轻和老年受试者的 MFE 在高视力增益时小于低视力增益，但仅在年轻受试者中，力的 SD 在高视力增益时小于低视力增益。