Variability of the relationship between electrophysiology and BOLD-fMRI across cortical regions in humans.
Variability of the relationship between electrophysiology and BOLD-fMRI across cortical regions in humans.
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DOI：
10.1523/jneurosci.1457-11.2011
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发表时间：
2011-09-07
期刊：
影响因子：
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通讯作者：
Tandon N
中科院分区：
文献类型：
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作者：
Conner CR;Ellmore TM;Pieters TA;DiSano MA;Tandon N
血氧水平依赖性 (BOLD) 功能 MRI (fMRI) 信号与人类潜在神经电活动之间的关系是系统神经科学非常感兴趣的话题。无论大脑区域和正在研究的认知任务如何，这种关系通常被认为是不变的。我们通过将 BOLD-fMRI 响应与植入了 1210 个硬膜下电极的 11 个人在视觉提示的常见名词和动词生成过程中的局部场电位 (LFP) 测量进行比较，批判性地评估了这些假设。正如预期的那样，中伽玛频段 (60 –120 Hz) 的功率与 BOLD 信号变化呈正相关 (r2 = 0.16，p < 10−16)，而 beta 频段 (13–30 Hz) 的功率与 BOLD 信号变化呈负相关 (r2 = 0.09，p < 10−16)。 β 和中伽马带活动独立地解释了观察到的 BOLD 信号的不同组成部分。重要的是，我们发现记录位点的位置（即脑叶）调节皮质电图（ECoG）信号和观察到的功能磁共振成像反应之间的关系（p < 10−16，F21,1830 = 52.7），而语言任务的类型则不然。在所有大脑区域中，伽马和贝塔带中的 ECoG 活动解释了 22% 的 fMRI 响应，但如果考虑脑叶位置，则可以解释 28% 的方差。在个体脑回水平上进一步评估这种关系提供了皮质位点之间 BOLD-LFP 关系差异的额外证据。 fMRI 信号和神经活动之间关系的这种空间变异性对血流动力学响应函数的建模具有影响，这是区域间 fMRI 比较的重要步骤。
The relationship between blood oxygenation level-dependent (BOLD) functional MRI (fMRI) signal and the underlying neural electrical activity in humans is a topic of intense interest to systems neuroscience. This relationship has generally been assumed to be invariant regardless of the brain region and the cognitive task being studied. We critically evaluated these assumptions by comparing the BOLD-fMRI response with local field potential (LFP) measurements during visually cued common noun and verb generation in 11 humans in whom 1210 subdural electrodes were implanted. As expected, power in the mid-gamma band (60 –120 Hz) correlated positively (r2 = 0.16, p < 10−16) and power in the beta band (13–30 Hz) correlated negatively (r2 = 0.09, p < 10−16) with the BOLD signal change. Beta and mid-gamma band activity independently explain different components of the observed BOLD signal. Importantly, we found that the location (i.e., lobe) of the recording site modulates the relationship between the electrocorticographic (ECoG) signal and the observed fMRI response (p < 10−16, F21,1830 = 52.7), while the type of language task does not. Across all brain regions, ECoG activity in the gamma and beta bands explains 22% of the fMRI response, but if the lobar location is considered, 28% of the variance can be explained. Further evaluation of this relationship at the level of individual gyri provides additional evidence of differences in the BOLD-LFP relationship by cortical locus. This spatial variability in the relationship between the fMRI signal and neural activity carries implications for modeling of the hemodynamic response function, an essential step for interregional fMRI comparisons.