Cordes D, Haughton V M, Arfanakis K, Wendt G J, Turski P A, Moritz C H, Quigley M A, Meyerand M E
Department of Medical Physics, University of Wisconsin, Madison, USA.
AJNR Am J Neuroradiol. 2000 Oct;21(9):1636-44.
In subjects who are performing no prescribed cognitive task, functional connectivity mapped with MR imaging (fcMRI) shows regions with synchronous fluctuations of cerebral blood flow. When specific tasks are performed, functional MR imaging (fMRI) can map locations in which regional cerebral blood flow increases synchronously with the performance of the task. We tested the hypothesis that fcMRI maps, based on the synchrony of low-frequency blood flow fluctuations, identify brain regions that show activation on fMRI maps of sensorimotor, visual, language, and auditory tasks.
In four volunteers, task-activation fMRI and functional connectivity (resting-state) fcMRI data were acquired. A small region of interest (in an area that showed maximal task activation) was chosen, and the correlation coefficient of the corresponding resting-state signal with the signal of all other voxels in the resting data set was calculated. The correlation coefficient was decomposed into frequency components and its distribution determined for each fcMRI map. The fcMRI maps were compared with the fMRI maps.
For each task, fcMRI maps based on one to four seed voxel(s) produced clusters of voxels in regions of eloquent cortex. For each fMRI map a closely corresponding fcMRI map was obtained. The frequencies that predominated in the cross-correlation coefficients for the functionally related regions were below 0.1 Hz.
Functionally related brain regions can be identified by means of their synchronous slow fluctuations in signal intensity. Such blood flow synchrony can be detected in sensorimotor areas, expressive and receptive language regions, and the visual cortex by fcMRI. Regions identified by the slow synchronous fluctuations are similar to those activated by motor, language, or visual tasks.
在未执行规定认知任务的受试者中，通过磁共振成像（fcMRI）绘制的功能连接显示出脑血流同步波动的区域。当执行特定任务时，功能磁共振成像（fMRI）可以绘制出区域脑血流与任务执行同步增加的位置。我们检验了这样一个假设，即基于低频血流波动同步性的fcMRI图谱能够识别在感觉运动、视觉、语言和听觉任务的fMRI图谱上显示激活的脑区。
对四名志愿者采集任务激活fMRI和功能连接（静息状态）fcMRI数据。选择一个小的感兴趣区域（在显示最大任务激活的区域），并计算相应静息状态信号与静息数据集中所有其他体素信号的相关系数。将相关系数分解为频率成分，并确定每个fcMRI图谱的分布。将fcMRI图谱与fMRI图谱进行比较。
对于每项任务，基于一到四个种子体素的fcMRI图谱在明确皮层区域产生了体素簇。对于每个fMRI图谱，都获得了一个与之密切对应的fcMRI图谱。功能相关区域互相关系数中占主导的频率低于0.1Hz。
功能相关的脑区可以通过其信号强度的同步缓慢波动来识别。通过fcMRI可以在感觉运动区、语言表达和接受区以及视觉皮层检测到这种血流同步性。由缓慢同步波动识别出的区域与由运动、语言或视觉任务激活的区域相似。
