Zhong Xiaole Z, Tong Yunjie, Chen J Jean
Rotman Research Institute at Baycrest, Toronto, ON, Canada.
Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.
Imaging Neurosci (Camb). 2024 May 20;2. doi: 10.1162/imag_a_00174. eCollection 2024.
In resting-state functional magnetic resonance imaging (rs-fMRI) functional connectivity (FC) mapping, temporal correlation is widely assumed to reflect synchronized neural-related activity. Although a large number of studies have demonstrated the potential vascular effects on FC, little research has been conducted on FC resulting from macrovascular signal fluctuations. Previously, our study found (Tong, Yao, et al., 2019) a robust anti-correlation between the fMRI signals in the internal carotid artery and the internal jugular vein (and the sagittal sinus). The present study extends the previous study to include all detectable major veins and arteries in the brain in a systematic analysis of the macrovascular contribution to the functional connectivity of the whole-gray matter (GM). This study demonstrates that: (1) The macrovasculature consistently exhibited strong correlational connectivity among itself, with the sign of the correlations varying between arterial and venous connectivity; (2) GM connectivity was found to have a strong macrovascular contribution, stronger from veins than arteries; (3) FC originating from the macrovasculature displayed disproportionately high spatial variability compared to that associated with all GM voxels; and (4) macrovascular contributions to connectivity were still evident well beyond the confines of the macrovascular space. These findings highlight the extensive contribution to rs-fMRI blood-oxygenation level-dependent (BOLD) and FC predominantly by large veins, but also by large arteries. These findings pave the way for future studies aimed at more comprehensively modeling and thereby removing these macrovascular contributions.
在静息态功能磁共振成像（rs-fMRI）功能连接（FC）图谱中，人们普遍认为时间相关性反映了同步的神经相关活动。尽管大量研究已经证明了血管对功能连接的潜在影响，但关于大血管信号波动导致的功能连接的研究却很少。此前，我们的研究（Tong, Yao, 等人，2019）发现颈内动脉和颈内静脉（以及矢状窦）中的功能磁共振成像信号之间存在强烈的反相关。本研究扩展了先前的研究，将大脑中所有可检测到的主要静脉和动脉纳入其中，系统分析大血管对全灰质（GM）功能连接的贡献。这项研究表明：（1）大血管自身之间始终表现出强烈的相关连接性，动脉和静脉连接之间的相关性符号不同；（2）发现GM连接性有很强的大血管贡献，静脉的贡献比动脉更强；（3）与所有GM体素相关的功能连接相比，源自大血管的功能连接显示出极高的空间变异性；（4）大血管对连接性的贡献在大血管空间范围之外仍然很明显。这些发现突出了大静脉以及大动脉对rs-fMRI血氧水平依赖（BOLD）和功能连接的广泛贡献。这些发现为未来旨在更全面地建模并消除这些大血管贡献的研究铺平了道路。
