Discrepancies between BOLD and flow dynamics in primary and supplementary motor areas: application of the balloon model to the interpretation of BOLD transients
Discrepancies between BOLD and flow dynamics in primary and supplementary motor areas: application of the balloon model to the interpretation of BOLD transients
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DOI：
10.1016/j.neuroimage.2003.08.040
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发表时间：
2004-01-01
期刊：
影响因子：
5.7
通讯作者：
Buxton, RB
中科院分区：
文献类型：
--
作者：
Obata, T;Liu, TT;Buxton, RB
在激活实验期间，用功能磁共振成像(FMRI)在大脑中测量的血氧水平依赖(BOLD)信号通常在刺激的开始和结束时显示出明显的瞬变。这种瞬变可能是潜在神经活动的瞬变的反映，也可能是脑血流量(CBF)、脑氧代谢率(CMRO2)或脑血容量(CBV)的瞬变造成的。使用动脉自旋标记(ASL)方法研究这些瞬变，该方法允许同时测量BOLD和CBF反应。测定了5名健康志愿者对手指敲击任务(S刺激40次，S休息80次)在主运动区(M1)和辅助运动区(SMA)的反应。在SMA，在刺激计划开始和结束时，平均大胆的反应是明显的，而在M1，大胆的反应几乎持平。然而，这两个区域的CBF反应相当相似，并没有表现出与SMA中的大胆反应相同的瞬时特征。由于这表明SMA中大胆反应的瞬变是血流动力学而不是神经起源，我们使用气球模型的一般化来测试产生测量曲线所需的血流动力学瞬变的程度。这两个数据集可以用CMRO2和CBV响应的形状略有不同来近似。这项研究阐明了使用理论模型结合ASL技术来理解大胆反应的动态的实用性和局限性。(C)2003 Elsevier Inc.保留所有权利。
The blood-oxygen-level-dependent (BOLD) signal measured in the brain with functional magnetic resonance imaging (fMRI) during an activation experiment often exhibits pronounced transients at the beginning and end of the stimulus. Such transients could be a reflection of transients in the underlying neural activity, or they could result from transients in cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO2), or cerebral blood volume (CBV). These transients were investigated using an arterial spin labeling (ASL) method that allows simultaneous measurements of BOLD and CBF responses. Responses to a finger-tapping task (40-s stimulus, 80-s rest) were measured in primary motor area (M1) and supplementary motor area (SMA) in five healthy volunteers. In SMA, the average BOLD response was pronounced near the beginning and end of the stimulus, while in M1, the BOLD response was nearly flat. However, CBF responses in the two regions were rather similar, and did not exhibit the same transient features as the BOLD response in SMA. Because this suggests a hemodynamic rather than a neural origin for the transients of the BOLD response in SMA, we used a generalization of the balloon model to test the degree of hemodynamic transients required to produce the measured curves. Both data sets could be approximated with modest differences in the shapes of the CMRO2 and CBV responses. This study illustrates the utility and the limitations of using theoretical models combined with ASL techniques to understand the dynamics of the BOLD response. (C) 2003 Elsevier Inc. All rights reserved.