Resting-state neural oscillations are used as biomarkers for functional diseases such as dementia, epilepsy, and stroke. However, accurate interpretation of clinical outcomes requires the identification and minimisation of potential confounding factors. While several studies have indicated that the menstrual cycle also alters brain activity, most of these studies were based on visual inspection rather than objective quantitative measures. In the present study, we aimed to clarify the effect of the menstrual cycle on spontaneous neural oscillations based on quantitative magnetoencephalography (MEG) parameters. Resting-state MEG activity was recorded from 25 healthy women with normal menstrual cycles. For each woman, resting-state brain activity was acquired twice using MEG: once during their menstrual period (MP) and once outside of this period (OP). Our results indicated that the median frequency and peak alpha frequency of the power spectrum were low, whereas Shannon spectral entropy was high, during the MP. Theta intensity within the right temporal cortex and right limbic system was significantly lower during the MP than during the OP. High gamma intensity in the left parietal cortex was also significantly lower during the MP than during the OP. Similar differences were also observed in the parietal and occipital regions between the proliferative (the late part of the follicular phase) and secretory phases (luteal phase). Our findings suggest that the menstrual cycle should be considered to ensure accurate interpretation of functional neuroimaging in clinical practice.

中文翻译：

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月经周期改变静息状态皮质活动：脑磁图研究

静息状态的神经振荡被用作痴呆、癫痫和中风等功能性疾病的生物标志物。然而，准确解释临床结果需要识别和最小化潜在的混杂因素。虽然几项研究表明月经周期也会改变大脑活动，但大多数这些研究都是基于目视检查而不是客观的定量测量。在本研究中，我们旨在基于定量脑磁图 (MEG) 参数阐明月经周期对自发神经振荡的影响。记录了 25 名月经周期正常的健康女性的静息状态 MEG 活性。对于每位女性，使用 MEG 获得两次静息状态的大脑活动：一次在月经期 (MP) 一次，一次在月经期 (OP) 之外。我们的结果表明，在 MP 期间，功率谱的中值频率和峰值 alpha 频率较低，而香农谱熵较高。MP 期间右侧颞叶皮层和右侧边缘系统内的 Theta 强度显着低于 OP。MP期间左顶叶皮层的高伽马强度也显着低于OP期间。在增殖期（卵泡期的后期）和分泌期（黄体期）之间的顶叶和枕叶区域也观察到了类似的差异。我们的研究结果表明，应考虑月经周期以确保在临床实践中准确解释功能性神经影像学。我们的结果表明，在 MP 期间，功率谱的中值频率和峰值 alpha 频率较低，而香农谱熵较高。MP 期间右侧颞叶皮层和右侧边缘系统内的 Theta 强度显着低于 OP。MP期间左顶叶皮层的高伽马强度也显着低于OP期间。在增殖期（卵泡期的后期）和分泌期（黄体期）之间的顶叶和枕叶区域也观察到了类似的差异。我们的研究结果表明，应考虑月经周期以确保在临床实践中准确解释功能性神经影像学。我们的结果表明，在 MP 期间，功率谱的中值频率和峰值 alpha 频率较低，而香农谱熵较高。MP 期间右侧颞叶皮层和右侧边缘系统内的 Theta 强度显着低于 OP。MP期间左顶叶皮层的高伽马强度也显着低于OP期间。在增殖期（卵泡期的后期）和分泌期（黄体期）之间的顶叶和枕叶区域也观察到了类似的差异。我们的研究结果表明，应考虑月经周期以确保在临床实践中准确解释功能性神经影像学。MP 期间右侧颞叶皮层和右侧边缘系统内的 Theta 强度显着低于 OP。MP期间左顶叶皮层的高伽马强度也显着低于OP期间。在增殖期（卵泡期的后期）和分泌期（黄体期）之间的顶叶和枕叶区域也观察到了类似的差异。我们的研究结果表明，应考虑月经周期以确保在临床实践中准确解释功能性神经影像学。MP 期间右侧颞叶皮层和右侧边缘系统内的 Theta 强度显着低于 OP。MP 期间左顶叶皮层的高伽马强度也显着低于 OP。在增殖期（卵泡期的后期）和分泌期（黄体期）之间的顶叶和枕叶区域也观察到了类似的差异。我们的研究结果表明，应考虑月经周期以确保在临床实践中准确解释功能性神经影像学。在增殖期（卵泡期的后期）和分泌期（黄体期）之间的顶叶和枕叶区域也观察到了类似的差异。我们的研究结果表明，应考虑月经周期以确保在临床实践中准确解释功能性神经影像学。在增殖期（卵泡期的后期）和分泌期（黄体期）之间的顶叶和枕叶区域也观察到了类似的差异。我们的研究结果表明，应考虑月经周期以确保在临床实践中准确解释功能性神经影像学。