Marinovic Welber, Boyd Reon, Nguyen An
School of Population Health, Discipline of Psychology, Curtin University, Australia.
Department of Health, Western Australia, Australia.
Neuroimage Rep. 2024 Jun 30;4(3):100212. doi: 10.1016/j.ynirp.2024.100212. eCollection 2024 Sep.
Motor preparation is a dynamic process that is tuned to task demands such as urgency. This study examined the effect of urgency to move on cortico-muscular coherence (CMC) in the beta frequency band during motor preparation. Participants (n = 25) prepared for a rapid wrist flexion movement under two distinct scenarios: high (350 ms to prepare) and low (1400 ms to prepare) urgency. Before participants performed the ballistic actions, they were required to hold a light contraction of the flexor carpi radialis muscle for 3 s. During this holding time, we simultaneously obtained EEG and EMG signals to estimate their coherence -a measure of how much brain and muscle activity is synchronized at specific rhythms- over the last 1 s of the contraction interval. Contrary to our hypothesis, we found greater CMC in conditions of low urgency rather than high urgency. This finding suggests that participants prioritized attending to the visual stimuli, dividing their attention to capture the preparation go-signal, rather than preparing the motor system, leading to a reduction in CMC. This interpretation suggests a cognitive-motor trade-off, wherein attentional resources are allocated more to sensory processing that to motor preparedness in urgent situations.
运动准备是一个动态过程，会根据诸如紧迫性等任务需求进行调整。本研究考察了在运动准备过程中，紧迫性对β频段皮质-肌肉相干性（CMC）的影响。参与者（n = 25）在两种不同情况下准备快速腕部屈曲运动：高紧迫性（350毫秒准备时间）和低紧迫性（1400毫秒准备时间）。在参与者进行弹道式动作之前，要求他们对桡侧腕屈肌进行3秒的轻度收缩。在这段保持时间内，我们同时获取脑电图（EEG）和肌电图（EMG）信号，以估计在收缩间隔的最后1秒内它们的相干性——一种衡量大脑和肌肉活动在特定节律下同步程度的指标。与我们的假设相反，我们发现在低紧迫性而非高紧迫性条件下，CMC更大。这一发现表明，参与者优先关注视觉刺激，分散注意力以捕捉准备开始信号，而不是准备运动系统，从而导致CMC降低。这一解释表明存在一种认知-运动权衡，即在紧急情况下，注意力资源更多地分配给感觉处理而非运动准备。
