265Korean J Radiol 13(3), May/Jun 2012kjronline.org MRI Study on the Functional and Spatial Consistency of Resting State-Related Independent Components of the

Objective: Resting-state networks (RSNs), including the default mode network (DMN), have been considered as markers of brain status such as consciousness, developmental change, and treatment effects. The consistency of functional connectivity among RSNs has not been fully explored, especially among resting-state-related independent components (RSICs). Materials and Methods: This resting-state fMRI study addressed the consistency of functional connectivity among RSICs as well as their spatial consistency between ‘at day 1 ’ and ‘after 4 weeks ’ in 13 healthy volunteers. Results: We found that most RSICs, especially the DMN, are reproducible across time, whereas some RSICs were variable in either their spatial characteristics or their functional connectivity. Relatively low spatial consistency was found in the basal ganglia, a parietal region of left frontoparietal network, and the supplementary motor area. The functional connectivity between two independent components, the bilateral angular/supramarginal gyri/intraparietal lobule and bilateral middle temporal/occipital gyri, was decreased across time regardless of the correlation analysis method employed (Pearson’s or partial correlation). Conclusion: RSICs showing variable consistency are different between spatial characteristics and functional connectivity. To understand the brain as a dynamic network, we recommend further investigation of both changes in the activation o