Data_Sheet_1_Effect of the Menstrual Cycle on Electroencephalogram Alpha and Beta Bands During Motor Imagery and Action Observation.pdf

Female sex steroids (FSS) can affect the motor system, modulating motor cortex excitability as well as performance in dexterity and coordination tasks. However, it has not yet been explored whether FSS affects the cognitive components of motor behavior. Mu is a sensorimotor rhythm observed by electroencephalography (EEG) in alpha (8–12 Hz) and beta (15–30 Hz) frequency bands in practices such as motor imagery (MI) and action observation (AO). This rhythm represents a window for studying the activity of neural circuits involved in motor cognition. Herein we investigated whether the alpha-mu and beta-mu power in the sensorimotor region (C3 and C4, hypothesis-driven approach) and the alpha and beta power over frontal, parietal, and occipital regions (data-driven approach) are modulated differently in the menstrual, follicular, and luteal phases of menstrual cycles in right-handed dominant women. To do so, these women underwent MI and AO in the three menstrual cycle phases. The spectral activity of the cortical regions for the alpha and beta bands were compared between phases of the menstrual cycle and a correlation analysis was also performed in relation to estrogen and progesterone levels. For the hypothesis-based approach, beta-mu event-related desynchronization (ERD) was significantly stronger in the C3 channel in the follicular phase than in the menstrual and luteal phases. For the data-driven approach, beta ERD during MI was higher in the follicular phase than in the menstrual and luteal phases in the frontal region. These findings suggest the effect of FSS on executive movement control. No effect of menstrual cycle phases was observed in cortical areas investigated during OA, but alpha and beta bands correlated positively with the follicular phase plasma estradiol level. Thus, the attenuation of alpha and beta bands referring to mirror neuron activities appears to be associated with inhibition of cortical activity when estradiol levels are lower, improving cognitive processing of motor action.

女性性激素（FSS）可影响运动系统，调节运动皮层的兴奋性以及灵巧和协调任务的表现。然而，尚未探讨FSS是否会影响运动行为的认知成分。Mu是一种通过脑电图（EEG）在α（8–12 Hz）和β（15–30 Hz）频段观察到的感觉运动节律，该节律在运动想象（MI）和动作观察（AO）等实践中得以体现。此节律代表了研究涉及运动认知的神经网络活动窗口。本研究旨在探究α-μ和β-μ功率在感觉运动区域（C3和C4，假设驱动方法）以及α和β功率在额叶、顶叶和枕叶区域（数据驱动方法）是否在月经、卵泡和黄体期月经周期中右利手女性的不同阶段呈现出不同的调节。为此，这些女性在三个月经周期阶段进行了MI和AO。比较了皮质区域在α和β频段的频谱活动，并针对雌激素和孕酮水平进行了相关分析。在基于假设的方法中，β-μ事件相关去同步（ERD）在卵泡期C3通道中显著强于月经期和黄体期。在数据驱动方法中，MI期间的β ERD在额叶区域在卵泡期高于月经期和黄体期。这些发现表明FSS对执行运动控制的影响。在OA过程中调查的皮质区域未观察到月经周期阶段的影响，但α和β频段与卵泡期血浆雌二醇水平呈正相关。因此，α和β频段的衰减，即指镜像神经元活动，似乎与雌二醇水平较低时皮质活动的抑制有关，从而提高了运动动作的认知处理。