Santarnecchi E, Biasella A, Tatti E, Rossi A, Prattichizzo D, Rossi S
Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, Brain Investigation & Neuromodulation Lab. (Si-BIN Lab), University of Siena, Italy; Berenson-Allen Center for Non-Invasive Brain Stimulation, Beth Israel Medical Center, Harvard Medical School, Boston, MA, USA; Siena Robotics and Systems Lab. (SIRS-Lab), Engineering and Mathematics Department, University of Siena, Italy.
Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, Brain Investigation & Neuromodulation Lab. (Si-BIN Lab), University of Siena, Italy.
Brain Res Bull. 2017 May;131:47-54. doi: 10.1016/j.brainresbull.2017.03.006. Epub 2017 Mar 18.
While the role of beta (∼20Hz), theta (∼5Hz) and alpha (∼10Hz) oscillations in the motor areas have been repeatedly associated with defined properties of motor performance, the investigation of gamma (∼40-90Hz) oscillatory activity is a more recent and still not fully understood component of motor control physiology, despite its potential clinical relevance for motor disorders.
OBJECTIVE/HYPOTHESIS: We have implemented an online neuromodulation paradigm based on transcranial alternating current stimulation (tACS) of the dominant motor cortex during a visuo-motor coordination task. This approach would allow a better understanding of the role of gamma activity, as well as that of other oscillatory bands, and their chronometry throughout the task.
We tested the effects of 5Hz, 20Hz, 60Hz (mid-gamma) 80Hz (high-gamma) and sham tACS on the performance of a sample of right-handed healthy volunteers, during a custom-made unimanual tracking task addressing several randomly occurring components of visuo-motor coordination (i.e., constant velocity or acceleration pursuits, turns, loops).
Data showed a significant enhancement of motor performance during high-gamma stimulation - as well as a trending effect for mid-gamma - with the effect being prominent between 200 and 500ms after rapid changes in tracking trajectory. No other effects during acceleration or steady pursuit were found.
Our findings posit a role for high-frequency motor cortex gamma oscillations during complex visuo-motor tasks involving the sudden rearrangement of motor plan/execution. Such a "prokinetic" effect of high-gamma stimulation might be worth to be tested in motor disorders, like Parkinson's disease, where the switching between different motor programs is impaired.
虽然运动区域中的β（约20Hz）、θ（约5Hz）和α（约10Hz）振荡的作用已反复与运动表现的特定属性相关联，但γ（约40 - 90Hz）振荡活动的研究是运动控制生理学中一个较新且仍未被完全理解的组成部分，尽管其对运动障碍具有潜在的临床相关性。
目的/假设：我们在视觉 - 运动协调任务期间实施了一种基于经颅交流电刺激（tACS）优势运动皮层的在线神经调节范式。这种方法将有助于更好地理解γ活动以及其他振荡频段的作用，以及它们在整个任务中的计时。
在一项定制的单手跟踪任务中，我们测试了5Hz、20Hz、60Hz（中γ）、80Hz（高γ）和假tACS对一组右利手健康志愿者表现的影响，该任务涉及视觉 - 运动协调的几个随机出现的组成部分（即匀速或加速追踪、转弯、环形）。
数据显示在高γ刺激期间运动表现有显著增强——中γ也有一定趋势——这种效应在跟踪轨迹快速变化后200至500毫秒之间最为显著。在加速或稳定追踪期间未发现其他效应。
我们的研究结果表明，在涉及运动计划/执行突然重新安排的复杂视觉 - 运动任务中，高频运动皮层γ振荡发挥作用。高γ刺激的这种“促动”效应可能值得在帕金森病等运动障碍中进行测试，在这些疾病中不同运动程序之间的切换受损。
