Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Centre Jülich, 52425, Jülich, Germany.
Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Centre Jülich, 52425, Jülich, Germany; Department of Neurology, University Hospital Cologne, 50924, Cologne, Germany.
Neuroimage. 2017 Oct 1;159:248-260. doi: 10.1016/j.neuroimage.2017.07.054. Epub 2017 Jul 26.
A consistent finding in motor EEG research is a bilateral attenuation of oscillatory activity over sensorimotor regions close to the onset of an upcoming unilateral hand movement. In contrast, little is known about how movement initiation affects oscillatory activity, especially in the hemisphere ipsilateral to the moving hand. We here investigated the neural mechanisms modulating oscillatory activity in the ipsilateral motor cortex prior to movement onset under the control of two different initiating networks, namely, Self-initiated and Visually-cued actions. During motor preparation, a contralateral preponderance of power over sensorimotor cortex (SM) was observed in α and β bands during Visually-cued movements, whereas power changes were more bilateral during Self-initiated movements. Coherence between ipsilateral SM (iSM) and contralateral SM (cSM) in the α-band was significantly increased compared to the respective baseline values, independent of the context of movement initiation. However, this context-independent cSM-iSM coherence modulated the power changes in iSM in a context-dependent manner, that is, a stronger cSM-iSM coherence correlated with a larger decrease in high-β power over iSM in the Self-initiated condition, in contrast to a smaller decrease in α power in the Visually-cued condition. In addition, the context-dependent coherence between SMA and iSM in the α-band and δ-θ-band for the Self-initiated and Visually-cued condition, respectively, exhibited a similar context-dependent modulation for power changes. Our findings suggest that the initiation of regional oscillations over iSM reflects changes in the information flow with the contralateral sensorimotor and premotor areas dependent upon the context of movement initiation. Importantly, the interaction between regional oscillations and network-like oscillatory couplings indicates different frequency-specific inhibitory mechanisms that modulate the activity in the ipsilateral sensorimotor cortex dependent upon how the movement is initiated.
运动脑电图研究中的一个一致发现是，在即将进行单侧手部运动开始时，靠近感觉运动区域的振荡活动会出现双侧衰减。相比之下，对于运动起始如何影响振荡活动，尤其是对移动手同侧半球，知之甚少。我们在此研究了在两种不同的起始网络（即自我发起和视觉提示动作）控制下，运动起始前同侧运动皮层中调节振荡活动的神经机制。在运动准备期间，在视觉提示运动中观察到 α 和 β 波段中对感觉运动皮层（SM）的优势对侧功率，而在自我发起运动中，功率变化则更为双侧。与各自的基线值相比，α 带中同侧 SM（iSM）和对侧 SM（cSM）之间的相干性显著增加，与运动起始的背景无关。然而，这种与背景无关的 cSM-iSM 相干性以背景相关的方式调节 iSM 中的功率变化，即更强的 cSM-iSM 相干性与自我发起条件下 iSM 中高β功率的更大降低相关，而在视觉提示条件下 α 功率的降低较小。此外，α 带中的 SMA 和 iSM 之间以及 δ-θ 带中的 SMA 和 iSM 之间的背景相关相干性分别为自我发起和视觉提示条件下的功率变化表现出类似的背景相关调制。我们的发现表明，iSM 上的区域振荡的起始反映了与对侧感觉运动和运动前区的信息流变化，这取决于运动起始的背景。重要的是，区域振荡和类似网络的振荡耦合之间的相互作用表明了不同频率特异性的抑制机制，这些机制取决于运动的发起方式，从而调节同侧感觉运动皮层的活动。
