Lapenta Olivia Morgan, Keller Peter E, Nozaradan Sylvie, Varlet Manuel
The MARCS Institute for Brain, Behaviour and Development, Western Sydney University, Penrith, Australia.
Center for Investigation in Psychology, University of Minho, Braga, Portugal.
Sci Rep. 2022 Apr 15;12(1):6271. doi: 10.1038/s41598-022-10342-5.
Human movements are spontaneously attracted to auditory rhythms, triggering an automatic activation of the motor system, a central phenomenon to music perception and production. Cortico-muscular coherence (CMC) in the theta, alpha, beta and gamma frequencies has been used as an index of the synchronisation between cortical motor regions and the muscles. Here we investigated how learning to produce a bimanual rhythmic pattern composed of low- and high-pitch sounds affects CMC in the beta frequency band. Electroencephalography (EEG) and electromyography (EMG) from the left and right First Dorsal Interosseus and Flexor Digitorum Superficialis muscles were concurrently recorded during constant pressure on a force sensor held between the thumb and index finger while listening to the rhythmic pattern before and after a bimanual training session. During the training, participants learnt to produce the rhythmic pattern guided by visual cues by pressing the force sensors with their left or right hand to produce the low- and high-pitch sounds, respectively. Results revealed no changes after training in overall beta CMC or beta oscillation amplitude, nor in the correlation between the left and right sides for EEG and EMG separately. However, correlation analyses indicated that left- and right-hand beta EEG-EMG coherence were positively correlated over time before training but became uncorrelated after training. This suggests that learning to bimanually produce a rhythmic musical pattern reinforces lateralised and segregated cortico-muscular communication.
人类的动作会自发地被听觉节奏所吸引，引发运动系统的自动激活，这是音乐感知和产生的核心现象。θ、α、β和γ频率的皮质-肌肉相干性（CMC）已被用作皮质运动区域与肌肉之间同步的指标。在这里，我们研究了学习产生由低音和高音组成的双手节奏模式如何影响β频段的CMC。在双手训练前后，当拇指和食指之间夹着力传感器并持续施加压力时，同时记录来自左右第一背侧骨间肌和指浅屈肌的脑电图（EEG）和肌电图（EMG），并让参与者聆听节奏模式。在训练过程中，参与者通过分别用左手或右手按压力传感器来产生低音和高音，从而在视觉线索的引导下学习产生节奏模式。结果显示，训练后总体β CMC或β振荡幅度没有变化，脑电图和肌电图左右两侧之间的相关性也没有变化。然而，相关性分析表明，训练前左右手β脑电图-肌电图相干性随时间呈正相关，但训练后变得不相关。这表明学习双手产生有节奏韵律模式加强了偏侧化和分离的皮质-肌肉交流。
