Center for Healthy Minds, University of Wisconsin-Madison, Madison, Wisconsin.
Waisman Laboratory for Brain Imaging and Behavior, University of Wisconsin-Madison, Madison, Wisconsin.
Eur J Neurosci. 2018 Sep;48(6):2310-2321. doi: 10.1111/ejn.14131.
Our recent finding of a meditation-related increase in low-frequency NREM sleep EEG oscillatory activities peaking in the theta-alpha range (4-12 Hz) was not predicted. From a consolidated body of research on sleep homeostasis, we would expect a change peaking in slow wave activity (1-4 Hz) following an intense meditation session. Here we compared these changes in sleep with the post-meditation changes in waking rest scalp power to further characterize their functional significance. High-density EEG recordings were acquired from 27 long-term meditators (LTM) on three separate days at baseline and following two 8-hr sessions of either mindfulness or compassion-and-loving-kindness meditation. Thirty-one meditation-naïve participants (MNP) were recorded at the same time points. As a common effect of meditation practice, we found increases in low and fast waking EEG oscillations for LTM only, peaking at eight and 15 Hz respectively, over prefrontal, and left centro-parietal electrodes. Paralleling our previous findings in sleep, there was no significant difference between meditation styles in LTM as well as no difference between matched sessions in MNP. Meditation-related changes in wakefulness and NREM sleep were correlated across space and frequency. A significant correlation was found in the EEG low frequencies (<12 Hz). Since the peak of coupling was observed in the theta-alpha oscillatory range, sleep homeostatic response to meditation practice is not sufficient to explain our findings. Another likely phenomenon into play is a reverberation of meditation-related processes during subsequent sleep. Future studies should ascertain the interplay between these processes in promoting the beneficial effects of meditation practice.
我们最近发现，冥想会导致低频非快速眼动睡眠 EEG 活动增加，峰值出现在θ-α波段（4-12 Hz），这是没有预料到的。从关于睡眠稳态的综合研究来看，我们预计在激烈的冥想后，会出现以慢波活动（1-4 Hz）为峰值的变化。在这里，我们将睡眠中的这些变化与冥想后的清醒静息头皮功率变化进行了比较，以进一步描述其功能意义。我们在三个不同的日子里，从 27 名长期冥想者（LTM）身上获取了高密度 EEG 记录，然后在基线和两次 8 小时的正念或慈悲与善意冥想之后进行了记录。同时也对 31 名没有冥想经验的参与者（MNP）进行了记录。作为冥想练习的共同影响，我们发现只有 LTM 的低和快波清醒 EEG 振荡增加，在前额叶和左中央顶叶电极处分别达到 8 和 15 Hz 的峰值。与我们之前在睡眠中发现的结果一致，LTM 中两种冥想方式之间没有显著差异，MNP 中匹配的冥想之间也没有差异。清醒和非快速眼动睡眠中的冥想相关变化在空间和频率上是相关的。在 EEG 低频（<12 Hz）中发现了显著的相关性。由于耦合的峰值出现在θ-α振荡范围内，因此，对冥想练习的睡眠稳态反应不足以解释我们的发现。另一种可能的现象是，在随后的睡眠中，冥想相关过程的回响。未来的研究应该确定这些过程在促进冥想练习的有益效果方面的相互作用。
