Di Nota Paula M, Chartrand Julie M, Levkov Gabriella R, Montefusco-Siegmund Rodrigo, DeSouza Joseph F X
Department of Psychology, York University, Toronto, ON, M3J 1P3, Canada.
Neuroscience Graduate Diploma Program, York University, Toronto, ON, M3J 1P3, Canada.
BMC Neurosci. 2017 Mar 6;18(1):28. doi: 10.1186/s12868-017-0349-0.
EEG studies investigating the neural networks that facilitate action observation (AO) and kinaesthetic motor imagery (KMI) have shown reduced, or desynchronized, power in the alpha (8-12 Hz) and beta (13-30 Hz) frequency bands relative to rest, reflecting efficient activation of task-relevant areas. Functional modulation of these networks through expertise in dance has been established using fMRI, with greater activation among experts during AO. While there is evidence for experience-dependent plasticity of alpha power during AO of dance, the influence of familiarity on beta power during AO, and alpha and beta activity during KMI, remain unclear. The purpose of the present study was to measure the impact of familiarity on confidence ratings and EEG activity during (1) AO of a brief ballet sequence, (2) KMI of this same sequence, and (3) KMI of non-dance movements among ballet dancers, dancers from other genres, and non-dancers.
Ballet dancers highly familiar with the genre of the experimental stimulus demonstrated higher individual alpha peak frequency (iAPF), greater alpha desynchronization, and greater task-related beta power during AO, as well as faster iAPF during KMI of non-dance movements. While no between-group differences in alpha or beta power were observed during KMI of dance or non-dance movements, all participants showed significant desynchronization relative to baseline, and further desynchronization during dance KMI relative to non-dance KMI indicative of greater cognitive load.
These findings confirm and extend evidence for experience-dependent plasticity of alpha and beta activity during AO of dance and KMI. We also provide novel evidence for modulation of iAPF that is faster when tuned to the specific motor repertoire of the observer. By considering the multiple functional roles of these frequency bands during the same task (AO), we have disentangled the compounded contribution of familiarity and expertise to alpha desynchronization for mediating task engagement among familiar ballet dancers and reflecting task difficulty among unfamiliar non-dance subjects, respectively. That KMI of a complex dance sequence relative to everyday, non-dance movements recruits greater cognitive resources suggests it may be a more powerful tool in driving neural plasticity of action networks, especially among the elderly and those with movement disorders.
脑电图研究调查了促进动作观察（AO）和动觉运动想象（KMI）的神经网络，结果显示相对于静息状态，阿尔法（8 - 12赫兹）和贝塔（13 - 30赫兹）频段的功率降低或去同步化，这反映了与任务相关区域的有效激活。通过功能磁共振成像（fMRI）已证实，舞蹈专业技能对这些神经网络具有功能调制作用，在动作观察期间，专家的激活程度更高。虽然有证据表明在舞蹈动作观察期间阿尔法功率存在经验依赖性可塑性，但熟悉程度对动作观察期间贝塔功率以及动觉运动想象期间阿尔法和贝塔活动的影响仍不明确。本研究的目的是测量熟悉程度对芭蕾舞演员、其他舞种的舞者和非舞者在以下情况时的信心评级和脑电图活动的影响：（1）简短芭蕾舞序列的动作观察；（2）同一序列的动觉运动想象；（3）非舞蹈动作的动觉运动想象。
对实验刺激类型高度熟悉的芭蕾舞演员在动作观察期间表现出更高的个体阿尔法峰值频率（iAPF）、更大的阿尔法去同步化以及更强的与任务相关的贝塔功率，在非舞蹈动作的动觉运动想象期间iAPF也更快。虽然在舞蹈或非舞蹈动作的动觉运动想象期间未观察到阿尔法或贝塔功率的组间差异，但所有参与者相对于基线均表现出显著的去同步化，并且在舞蹈动觉运动想象期间相对于非舞蹈动觉运动想象有进一步的去同步化，表明认知负荷更大。
这些发现证实并扩展了关于舞蹈动作观察和动觉运动想象期间阿尔法和贝塔活动的经验依赖性可塑性的证据。我们还提供了新的证据，表明当根据观察者的特定运动技能进行调整时，个体阿尔法峰值频率的调制更快。通过考虑这些频段在同一任务（动作观察）期间的多种功能作用，我们分别厘清了熟悉程度和专业技能对阿尔法去同步化的复合贡献，这对于熟悉的芭蕾舞演员中介任务参与以及反映不熟悉的非舞蹈受试者的任务难度具有重要意义。复杂舞蹈序列的动觉运动想象相对于日常非舞蹈动作需要更多认知资源，这表明它可能是驱动动作网络神经可塑性的更强大工具，尤其是在老年人和患有运动障碍的人群中。
