Movement and Cognitive Rehabilitation Science Program, Department of Kinesiology and Health Education, University of Texas at Austin, Austin, TX, USA; Human Cortical Physiology and Neurorehabilitation Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
Human Cortical Physiology and Neurorehabilitation Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
Brain Stimul. 2021 Jul-Aug;14(4):873-883. doi: 10.1016/j.brs.2021.05.009. Epub 2021 May 25.
Skill learning engages offline activity in the primary motor cortex (M1). Sensorimotor cortical activity oscillates between excitatory trough and inhibitory peak phases of the mu (8-12 Hz) rhythm. We recently showed that these mu phases influence the magnitude and direction of neuroplasticity induction within M1. However, the contribution of M1 activity during mu peak and trough phases to human skill learning has not been investigated.
To evaluate the effects of phase-dependent TMS during mu peak and trough phases on offline learning of a newly-acquired motor skill.
On Day 1, three groups of healthy adults practiced an explicit motor sequence learning task with their non-dominant left hand. After practice, phase-dependent TMS was applied to the right M1 during either mu peak or mu trough phases. The third group received sham TMS during random mu phases. On Day 2, all subjects were re-tested on the same task to evaluate offline learning.
Subjects who received phase-dependent TMS during mu trough phases showed increased offline skill learning compared to those who received phase-dependent TMS during mu peak phases or sham TMS during random mu phases. Additionally, phase-dependent TMS during mu trough phases elicited stronger whole-brain broadband oscillatory power responses than phase-dependent TMS during mu peak phases.
We conclude that sensorimotor mu trough phases reflect brief windows of opportunity during which TMS can strengthen newly-acquired skill memories.
技能学习会在初级运动皮层（M1）中引发离线活动。感觉运动皮层的活动在 mu（8-12 Hz）节律的兴奋性低谷和抑制性峰值相位之间振荡。我们最近表明，这些 mu 相位会影响 M1 内神经可塑性诱导的幅度和方向。然而，M1 在 mu 峰值和低谷相位期间的活动对人类技能学习的贡献尚未得到研究。
评估 mu 峰值和低谷相位中与相位相关的 TMS 对新获得运动技能的离线学习的影响。
在第 1 天，三组健康成年人用非主导的左手练习明确的运动序列学习任务。练习后，在 mu 峰值或 mu 低谷相位期间，将与相位相关的 TMS 施加到右侧 M1。第三组在随机 mu 相位期间接受假 TMS。在第 2 天，所有受试者在相同任务上重新进行测试，以评估离线学习。
与在 mu 峰值相位接受与相位相关的 TMS 或在随机 mu 相位接受假 TMS 的受试者相比，在 mu 低谷相位接受与相位相关的 TMS 的受试者表现出更大的离线技能学习。此外，与在 mu 峰值相位接受与相位相关的 TMS 相比，在 mu 低谷相位接受与相位相关的 TMS 会引起更强的全脑宽带振荡功率反应。
我们得出结论，感觉运动 mu 低谷相位反映了 TMS 可以增强新获得的技能记忆的短暂机会窗口。
