Cortical layer-dependent dynamic blood oxygenation, cerebral blood flow and cerebral blood volume responses during visual stimulation
Cortical layer-dependent dynamic blood oxygenation, cerebral blood flow and cerebral blood volume responses during visual stimulation
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DOI：
10.1016/j.neuroimage.2008.06.029
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发表时间：
2008-10-15
期刊：
影响因子：
5.7
通讯作者：
Kim, Seong-Gi
中科院分区：
文献类型：
--
作者：
Jin, Tao;Kim, Seong-Gi
脑血容量（CBV）和血流（CBF）响应的时空特征对于理解神经血管耦合机制和血氧水平依赖（BOLD）信号具有重要意义。为此，皮质层依赖的BOLD，CBV和CBF的反应进行了测量，在猫的视觉皮层功能磁共振成像。主要发现是：（i）时间依赖性的功能磁共振成像皮层轮廓是依赖于成像方式。总的来说，对于BOLD，穿过皮质的峰值出现在皮质表面，但是对于CBV和CBF，峰值出现在中间皮质层。与初始刺激期（4-10 s）相比，CBV对皮层中层的空间特异性在以后显著增加，而BOLD和CBF的特异性略有变化。(ii)在含有大软膜血管的上皮层区域的CBV响应具有比在相同区域的BOLD响应更快的起始时间和达到峰值的时间，并且具有比在具有微血管的中皮层区域的CBV更快的达到峰值的时间。这表明皮质中部微血管的扩张是随着皮质表面动脉容积的增加而发生的。(iii)对于所有这三种方式，刺激后的下冲观察与60秒的刺激范例，表明刺激后BOLD下冲不能解释延迟静脉CBV恢复理论在我们的实验条件下。(iv)CBV和CBF反应之间的关系是空间和时间依赖性的。因此，单一的幂律比例常数（伽马值）可能不适用于高分辨率研究。(C)2008年爱思唯尔公司所有的战斗保留。
The spatiotemporal characteristics of cerebral blood volume (CBV) and flow (CBF) responses are important for understanding neurovascular coupling mechanisms and blood oxygenation level-dependent (BOLD) signals. For this, cortical layer-dependent BOLD, CBV and CBF responses were measured at the cat visual cortex using fMRI. Major findings are: (i) the time-dependent fMRI cortical profile is dependent on imaging modality. Overall, the peak across the cortex occurs at the cortical surface for BOLD, but at the middle cortical layer for CBV and CBF. Compared to an initial stimulation period (4-10 s), the spatial specificity of CBV to the middle cortical layer increases significantly at a later time, while the specificity of BOLD and CBF slightly changes. (ii) The CBV response at the upper cortical area containing large pial vessels has a faster onset time and time to peak than the BOLD response at the same area, and a faster time to peak than CBV at the middle cortical area with microvessels. This Suggests that the dilation of microvessels at the middle cortical area follows arterial volume increase at the surface of the cortex. (iii) For all three modalities, the post-stimulus undershoot was observed with the 60-s stimulation paradigm, indicating that the post-stimulus BOLD undershoot cannot be explained by the delayed venous CBV recovery theory under our experimental conditions. (iv) The relationship between CBV and CBF responses is both spatially and temporally dependent. Thus, a single power-law scaling constant (gamma value) may not be applicable for high-resolution study. (C) 2008 Elsevier Inc. All fights reserved.