BioDesign Lab, School of Engineering, Computer and Mathematical Sciences, Auckland University of Technology, Auckland, New Zealand.
New Zealand College of Chiropractic, Auckland, New Zealand.
Sci Rep. 2022 Jan 11;12(1):520. doi: 10.1038/s41598-021-04461-8.
Airflow through the left-and-right nostrils is said to be entrained by an endogenous nasal cycle paced by both poles of the hypothalamus. Yogic practices suggest, and scientific evidence demonstrates, that right-nostril breathing is involved with relatively higher sympathetic activity (arousal states), while left-nostril breathing is associated with a relatively more parasympathetic activity (stress alleviating state). The objective of this study was to further explore this laterality by controlling nasal airflow and observing patterns of cortical activity through encephalographic (EEG) recordings. Thirty subjects participated in this crossover study. The experimental session consisted of a resting phase (baseline), then a period of unilateral nostril breathing (UNB) using the dominant nasal airway, followed by UNB using the non-dominant nasal airway. A 64-channel EEG was recorded throughout the whole session. The effects of nostril-dominance, and nostril-lateralization were assessed using the power spectral density of the neural activity. The differences in power-spectra and source localization were calculated between EEG recorded during UNB and baseline for delta, theta, alpha, beta and gamma bands. Cluster-based permutation tests showed that compared to baseline, EEG spectral power was significantly (1) decreased in all frequency bands for non-dominant nostril UNB, (2) decreased in alpha, beta and gamma bands for dominant nostril UNB, (3) decreased in all bands for left nostril UNB, and (4) decreased in all bands except delta for right nostril UNB. The beta band showed the most widely distributed changes across the scalp. our source localisation results show that breathing with the dominant nostril breathing increases EEG power in the left inferior frontal (alpha band) and left parietal lobule (beta band), whereas non-dominant nostril breathing is related to more diffuse and bilateral effects in posterior areas of the brain.These preliminary findings may stimulate further research in the area, with potential applications to tailored treatment of brain disorders associated with disruption of sympathetic and parasympathetic activity.
左右鼻孔的气流据说被下丘脑两极所主导的内源性鼻周期带动。瑜伽练习表明，科学证据也证明，右鼻孔呼吸与相对较高的交感神经活动（觉醒状态）有关，而左鼻孔呼吸则与相对更高的副交感神经活动（缓解压力状态）有关。本研究的目的是通过控制鼻气流并通过脑电图（EEG）记录观察皮质活动模式，进一步探索这种偏侧性。30 名受试者参加了这项交叉研究。实验阶段包括休息阶段（基线），然后使用优势鼻腔气道进行单侧鼻孔呼吸（UNB）一段时间，然后使用非优势鼻腔气道进行 UNB。在整个阶段都记录了 64 通道 EEG。使用神经活动的功率谱密度评估鼻孔优势和鼻孔偏侧性的影响。在 delta、theta、alpha、beta 和 gamma 波段，通过比较 UNB 和基线时记录的 EEG，计算了功率谱和源定位的差异。基于聚类的置换检验显示，与基线相比，（1）非优势鼻孔 UNB 时所有频带的 EEG 频谱功率均显著降低，（2）优势鼻孔 UNB 时 alpha、beta 和 gamma 带的功率降低，（3）左鼻孔 UNB 时所有频带的功率降低，（4）除右鼻孔 UNB 的 delta 带外，所有频带的功率均降低。beta 波段在头皮上的分布最广。我们的源定位结果表明，用优势鼻孔呼吸会增加左额下回（alpha 波段）和左顶叶（beta 波段）的 EEG 功率，而用非优势鼻孔呼吸与大脑后部更广泛和双侧的效应有关。这些初步发现可能会刺激该领域的进一步研究，为与交感神经和副交感神经活动中断相关的大脑障碍的针对性治疗提供潜在应用。
