Holper L, Scholkmann F, Seifritz E
Department of Psychiatry, Psychotherapy, and Psychosomatics, Psychiatric Hospital, University of Zurich, Lenggstrasse 31, CH-8032, Zürich, Switzerland.
Biomedical Optics Research Laboratory, Department of Neonatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
Brain Imaging Behav. 2017 Apr;11(2):461-472. doi: 10.1007/s11682-016-9527-4.
Brain activity has been shown to be influenced by respiratory behavior. Here, we evaluated whether respiration-induced hypo- or hypercapnia may support differentiation between physiological versus pathological respiratory behavior. In particular, we investigated whether systemic physiological measures could predict the brain's time-frequency hemodynamics after three respiratory challenges (i.e., breath-holding, rebreathing, and hyperventilation) compared to resting-state. Prefrontal hemodynamics were assessed in healthy subjects (N = 27) using functional near-infrared spectroscopy (fNIRS). Systemic physiological measures were assessed in form of heart rate, partial end-tidal carbon dioxide, respiration rate, and saturation of peripheral oxygen. Time-frequency dynamics were quantified using the wavelet transform coherence (i.e., defined here as cortical-systemic coherence). We found that the three respiratory challenges modulated cortical-systemic coherence differently: (1) After rebreathing, cortical-systemic coherence could be predicted from the amplitude of the heart rate (strong negative correlation). (2) After breath-holding, the same observation was made (moderate negative correlation). (3) After hyperventilation, no significant effect was observed. (4) These effects were found only in the frequency range of very low-frequency oscillations. The presented findings highlight a distinct role of rebreathing in predicting cortical-systemic coupling based on heart rate changes, which may represents a measure of affective states in the brain. The applied multimodal assessment of hemodynamic and systemic physiological measures during respiratory challenges may therefore have potential applications in the differentiation between physiological and pathological respiratory behavior.
大脑活动已被证明会受到呼吸行为的影响。在此，我们评估了呼吸诱导的低碳酸血症或高碳酸血症是否有助于区分生理性与病理性呼吸行为。具体而言，我们研究了与静息状态相比，全身生理指标能否预测三种呼吸挑战（即屏气、重复呼吸和过度通气）后大脑的时频血流动力学变化。使用功能近红外光谱技术（fNIRS）对27名健康受试者的前额叶血流动力学进行评估。以心率、呼气末二氧化碳分压、呼吸频率和外周血氧饱和度的形式评估全身生理指标。使用小波变换相干性（此处定义为皮质-全身相干性）对时频动态进行量化。我们发现，三种呼吸挑战对皮质-全身相干性的调节方式不同：（1）重复呼吸后，可根据心率幅度预测皮质-全身相干性（强负相关）。（2）屏气后，也有相同的观察结果（中度负相关）。（3）过度通气后，未观察到显著影响。（4）这些影响仅在极低频振荡的频率范围内被发现。本研究结果突出了重复呼吸在基于心率变化预测皮质-全身耦合方面的独特作用，这可能代表了大脑情感状态的一种度量。因此，在呼吸挑战期间应用的血流动力学和全身生理指标的多模态评估可能在生理性和病理性呼吸行为的区分中具有潜在应用价值。
