Gold Benjamin P, Goodale Sarah E, Zhao Chong, Pourmotabbed Haatef, de Zwart Jacco A, Özbay Pinar S, Bolt Taylor S, Duyn Jeff H, Chen Jingyuan E, Chang Catie
Department of Electrical and Computer Engineering, Vanderbilt University, Nashville, TN, United States.
Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, United States.
Imaging Neurosci (Camb). 2024 Sep 13;2. doi: 10.1162/imag_a_00287. eCollection 2024.
Vigilance naturally drifts over time, coinciding with marked changes in brain-wide functional magnetic resonance imaging (fMRI) signals. Though the precise origins of these hemodynamic changes are unclear, largely separate lines of research have linked different vigilance levels not only to changes in fMRI signal fluctuation amplitudes and functional connectivity, but also to significant variations in autonomic physiology. These findings raise the possibility that vigilance-related modulations in fMRI signals may arise in part from changes in autonomic physiology and their effects on cerebral hemodynamics. Here, using simultaneous recordings of fMRI, EEG-indexed vigilance, respiration, and pulse oximetry, we investigate how the relationship between autonomic and fMRI signals varies systematically as vigilance gradually drifts. Regression analyses indicated that the strength and extent of fMRI-autonomic covariation increased as vigilance diminished, during both resting state and an auditory vigilance task. Spatiotemporally, autonomic signals exhibited early positive correlations and delayed negative correlations with fMRI signals throughout much of the grey matter, accompanied by late positive correlations in the ventricles and periventricular white matter. Low-frequency EEG power fluctuations also demonstrated state-dependent associations with both fMRI and autonomic signals, with effects in fMRI that partially overlapped with those of peripheral autonomic variations. Functional connectivity between most brain networks strengthened as vigilance decreased, especially during resting-state scans, and removing autonomic variance from fMRI signals largely attenuated this effect. Together, these results demonstrate interactions between vigilance levels, autonomic physiology, and brain hemodynamics, showing that the physiological constituents of fMRI signals vary markedly over vigilance levels and brain regions. These findings contribute to knowledge of human brain physiology and toward the accurate parsing, analysis, and interpretation of fMRI data.
随着时间的推移，警觉性会自然波动，这与全脑功能磁共振成像（fMRI）信号的显著变化相一致。尽管这些血液动力学变化的确切起源尚不清楚，但大量独立的研究线路不仅将不同的警觉水平与fMRI信号波动幅度和功能连接性的变化联系起来，还与自主神经生理学的显著变化联系起来。这些发现增加了一种可能性，即fMRI信号中与警觉性相关的调制可能部分源于自主神经生理学的变化及其对脑血液动力学的影响。在这里，我们通过同时记录fMRI、脑电图索引的警觉性、呼吸和脉搏血氧饱和度，研究随着警觉性逐渐波动，自主神经和fMRI信号之间的关系如何系统地变化。回归分析表明，在静息状态和听觉警觉任务期间，随着警觉性降低，fMRI与自主神经的协变强度和程度增加。在时空上，自主神经信号在大部分灰质中与fMRI信号呈现早期正相关和延迟负相关，同时在脑室和脑室周围白质中呈现晚期正相关。低频脑电图功率波动也显示出与fMRI和自主神经信号的状态依赖性关联，其在fMRI中的影响部分与外周自主神经变化的影响重叠。随着警觉性降低，大多数脑网络之间的功能连接性增强，尤其是在静息状态扫描期间，从fMRI信号中去除自主神经方差在很大程度上减弱了这种影响。总之，这些结果证明了警觉水平、自主神经生理学和脑血液动力学之间的相互作用，表明fMRI信号的生理成分在警觉水平和脑区上有显著变化。这些发现有助于了解人类脑生理学，并有助于准确解析、分析和解释fMRI数据。
