Zhang Xiangzi, Zhang Shengyao, Zhang Haoyuan, Wang Houmin, Long Jinyi
School of Psychology, Northwest Normal University, Lanzhou, Gansu, China,730070.
College of Basic Medicine, Jinzhou Medical University, Jinzhou, Liaoning, China, 121001.
eNeuro. 2025 Mar 11;12(3). doi: 10.1523/ENEURO.0370-24.2025.
Beta event-related spectral perturbation (ERSP), including bilateral movement-related beta desynchronization (MRBD) and post-movement beta synchronization (PMBS), can be evoked by unilateral speed movement. A potential correlation might exist between power (de)synchronization and interhemispheric coherence during movement execution. However, during the PMBS phase, the existence of interhemispheric coupling and the effect of speed on it are largely undiscovered. This study aimed to answer this question. In the present study, we investigated eight healthy, right-handed volunteers using a combination of electroencephalography (EEG), transcranial magnetic stimulation (TMS), and electromyography (EMG). We explored interhemispheric (directed) coherence during isotonic right index finger abduction movements at two speeds: ballistic and self-paced. We discovered that: (i) Compared to the MRBD period, interhemispheric coherence was greater during the PMBS period. Furthermore, ballistic movement induced a larger coherence during the PMBS period, but not during the MRBD period. (ii) In the MRBD phase, directed coherence from the contralateral motor cortex (CM1) to the ipsilateral motor cortex (IM1) was larger, with a reverse tendency observed during the PMBS period. Additionally, in ballistic movement, directed coherence from IM1 to CM1 was stronger and positively correlated with coherence, with no effect of speed on directed coherence detected in the MRBD phase. To advance the understanding of neural mechanisms and the causality of interhemispheric coherence during the PMBS period, we investigated the interhemispheric inhibition (IHI) from IM1 to CM1 at different speeds. A stronger IHI from IM1 to CM1 at PMBS peak time was demonstrated, which was enhanced during ballistic movement. Additionally, IHI was negatively correlated with PMBS, and movement speed was positively associated with interhemispheric coupling during the PMBS period and IHI from IM1 to CM1. The present study explored interhemispheric (directed)coherence during isotonic right index finger abduction movements at two speeds: ballistic and self-paced. We discovered a dominance of interhemispheric coherence during the PMBS period of ballistic movement. Furthermore, directed coherence from the CM1 to the IM1 was more predominant in the MRBD phase, with a reverse tendency observed during the PMBS period. Additionally, directed coherence from IM1 to CM1 was stronger and positively correlated with coherence in ballistic movement. Advanced exploration revealed a stronger IHI from IM1 to CM1 at PMBS peak time, which was enhanced during ballistic movement. Additionally, IHI was negatively correlated with PMBS, and movement speed was positively associated with interhemispheric coupling during the PMBS period and IHI.
β事件相关频谱微扰（ERSP），包括双侧运动相关β去同步化（MRBD）和运动后β同步化（PMBS），可由单侧速度运动诱发。在运动执行过程中，功率（去）同步化与半球间相干性之间可能存在潜在关联。然而，在PMBS阶段，半球间耦合的存在及其速度效应在很大程度上尚未被发现。本研究旨在回答这个问题。在本研究中，我们使用脑电图（EEG）、经颅磁刺激（TMS）和肌电图（EMG）相结合的方法，对8名健康的右利手志愿者进行了研究。我们探讨了在两种速度下（快速和自定节奏）等张右食指外展运动过程中的半球间（定向）相干性。我们发现：（i）与MRBD期相比，PMBS期的半球间相干性更强。此外，快速运动在PMBS期诱发的相干性更大，但在MRBD期则不然。（ii）在MRBD阶段，从对侧运动皮层（CM1）到同侧运动皮层（IM1）的定向相干性更大，而在PMBS期观察到相反的趋势。此外，在快速运动中，从IM1到CM1的定向相干性更强，且与相干性呈正相关，在MRBD阶段未检测到速度对定向相干性的影响。为了进一步了解PMBS期半球间相干性的神经机制和因果关系，我们研究了不同速度下从IM1到CM1的半球间抑制（IHI）。结果表明，在PMBS峰值时间从IM1到CM1的IHI更强，在快速运动期间增强。此外，IHI与PMBS呈负相关，运动速度与PMBS期的半球间耦合以及从IM1到CM1的IHI呈正相关。本研究探讨了在两种速度下（快速和自定节奏）等张右食指外展运动过程中的半球间（定向）相干性。我们发现在快速运动的PMBS期半球间相干性占主导。此外，在MRBD阶段从CM1到IM1的定向相干性更显著，在PMBS期观察到相反的趋势。此外，在快速运动中从IM1到CM1的定向相干性更强，且与相干性呈正相关。进一步的研究表明，在PMBS峰值时间从IM1到CM1的IHI更强，在快速运动期间增强。此外，IHI与PMBS呈负相关，运动速度与PMBS期的半球间耦合以及IHI呈正相关。
