Mapping functionally related regions of brain with functional connectivityMR imaging

BACKGROUND AND PURPOSE: In subjects who are performing no prescribed cognit ive task, functional connectivity mapped with MR imaging (fcMRI) shows regi ons with synchronous fluctuations of cerebral blood how, When specific task s are performed, functional MR imaging (fMRI) can map locations in which re gional 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 how fluctuations, identify brain regions that show a ctivation on fMRI maps of sensorimotor, visual, language, and auditory task s, METHODS: In four volunteers, task-activation fMRI and functional connectivi ty (resting-state) fcMRI data were acquired. A small region of interest tin an area that showed maximal task activation) was chosen, and the correlati on coefficient of the corresponding resting-state signal with the signal of all other voxels in the resting data set was calculated, The correlation c oefficient was decomposed into frequency components and its distribution de termined for each fcMRI map. The fcMRI maps were compared with the fMRI map s. RESULTS: For each task, fcMRI maps based on one to four seed voxel(s) produ ced clusters of voxels in regions of eloquent cortex. For each fMRI map a c losely corresponding fcMRI map was obtained. The frequencies that predomina ted in the cross-correlation coefficients for the functionally related regi ons mere below 0.1 Hz, CONCLUSION: Functionally related brain regions can be identified by means o f their synchronous slow fluctuations in signal intensity, Such blood flow synchrony can be detected in sensorimotor areas, expressive and receptive l anguage regions, and the visual cortex by fcMRI, Regions identified by the slow synchronous fluctuations are similar to those activated by motor, lang uage, or visual tasks.