Liu Xiao, de Zwart Jacco A, Schölvinck Marieke L, Chang Catie, Ye Frank Q, Leopold David A, Duyn Jeff H
Advanced MRI Section, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
Multimodal and Computational Neuroimaging Laboratory, Department of Biomedical Engineering, The Pennsylvania State University, Pennsylvania, PA 16802, USA.
Nat Commun. 2018 Jan 26;9(1):395. doi: 10.1038/s41467-017-02815-3.
Cortical activity during periods of rest is punctuated by widespread, synchronous events in both electrophysiological and hemodynamic signals, but their behavioral relevance remains unclear. Here we report that these events correspond to momentary drops in cortical arousal and are associated with activity changes in the basal forebrain and thalamus. Combining fMRI and electrophysiology in macaques, we first establish that fMRI transients co-occur with spectral shifts in local field potentials (LFPs) toward low frequencies. Applying this knowledge to fMRI data from the human connectome project, we find that the fMRI transients are strongest in sensory cortices. Surprisingly, the positive cortical transients occur together with negative transients in focal subcortical areas known to be involved with arousal regulation, most notably the basal forebrain. This subcortical involvement, combined with the prototypical pattern of LFP spectral shifts, suggests that commonly observed widespread variations in fMRI cortical activity are associated with momentary drops in arousal.
在休息期间，皮层活动被电生理和血流动力学信号中广泛的同步事件所打断，但其行为相关性仍不清楚。在此我们报告，这些事件对应于皮层觉醒的瞬间下降，并与基底前脑和丘脑的活动变化相关。我们在猕猴中结合功能磁共振成像（fMRI）和电生理学方法，首先确定fMRI瞬变与局部场电位（LFP）频谱向低频的偏移同时出现。将这一认识应用于人类连接组计划的fMRI数据，我们发现fMRI瞬变在感觉皮层中最为强烈。令人惊讶的是，皮层正性瞬变与已知参与觉醒调节的局灶性皮层下区域（最显著的是基底前脑）的负性瞬变同时出现。这种皮层下的参与，结合LFP频谱偏移的典型模式，表明在fMRI皮层活动中常见的广泛变化与觉醒的瞬间下降有关。
