The many layers of BOLD. The effect of hypercapnic and hyperoxic stimuli on macro- and micro-vascular compartments quantified by CVR, M, and CBV across cortical depth.
The many layers of BOLD. The effect of hypercapnic and hyperoxic stimuli on macro- and micro-vascular compartments quantified by CVR, M, and CBV across cortical depth.
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DOI：
10.1177/0271678x221133972
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发表时间：
2023-03
影响因子：
6.3
通讯作者：
Petridou, Natalia
中科院分区：
文献类型：
--
作者：
Schellekens, Wouter;Bhogal, Alex A.;Roefs, Emiel C. A.;Baez-Yanez, Mario G.;Siero, Jeroen C. W.;Petridou, Natalia
超高场功能性磁共振成像（fMRI）提供了空间分辨率来测量皮质层尺度上的神经元活动。然而，皮质深度依赖性血管化的差异，如软脑膜表面附近的大血管室的患病率较高，有混淆效应的深度分辨血氧水平依赖（BOLD）的功能磁共振成像信号。在目前的研究中，我们使用高碳酸血症和高氧呼吸条件下，量化的影响，所有静脉血管和微血管隔室层流BOLD功能磁共振成像，测量梯度回波（GE）和自旋回波（SE）扫描序列，分别。我们发现，所有的静脉血管和微血管室是能够比较的理论最大信号强度，所代表的M值参数。然而，血管扩张的能力，如脑血管反应性（CVR）所反映的，与浅表层的微血管系统相比，所有静脉血管隔室组合的血管扩张能力约为2.5倍。最后，所有静脉血管和微血管间室的CBV变化估计值存在约35%的差异，尽管这种相对差异在皮质深度上大致一致。因此，我们的研究结果表明，功能磁共振成像BOLD信号的差异，整个皮层深度可能是由大血管和微血管室之间的扩张特性的差异。
Ultra-high field functional magnetic resonance imaging (fMRI) offers the spatial resolution to measure neuronal activity at the scale of cortical layers. However, cortical depth dependent vascularization differences, such as a higher prevalence of macro-vascular compartments near the pial surface, have a confounding effect on depth-resolved blood-oxygen-level dependent (BOLD) fMRI signals. In the current study, we use hypercapnic and hyperoxic breathing conditions to quantify the influence of all venous vascular and micro-vascular compartments on laminar BOLD fMRI, as measured with gradient-echo (GE) and spin-echo (SE) scan sequences, respectively. We find that all venous vascular and micro-vascular compartments are capable of comparable theoretical maximum signal intensities, as represented by the M-value parameter. However, the capacity for vessel dilation, as reflected by the cerebrovascular reactivity (CVR), is approximately two and a half times larger for all venous vascular compartments combined compared to the micro-vasculature at superficial layers. Finally, there is roughly a 35% difference in estimates of CBV changes between all venous vascular and micro-vascular compartments, although this relative difference was approximately uniform across cortical depth. Thus, our results suggest that fMRI BOLD signal differences across cortical depth are likely caused by differences in dilation properties between macro- and micro-vascular compartments.