title: Functional connectivity during resting-state functional MR imaging: study of the correspondence between independent component analysis and region-of-interest-based methods.
abstract: OBJECTIVE
  The connectivity across brain regions can be evaluated through fMRI either by using ICA or by means of correlation analysis of time courses measured in predefined ROIs. The purpose of this study was to investigate quantitatively the correspondence between the connectivity information provided by the 2 techniques.
  
  
  METHODS
  In this study, resting-state fMRI data from 40 healthy participants were independently analyzed by using spatial ICA and ROI-based analysis. To assess the correspondence between the results provided by the 2 methods, for all combinations of ROIs, we compared the time course correlation coefficient with the corresponding "ICA coactivation index."
  
  
  RESULTS
  A strongly significant correspondence of moderate intensity was found for 20 ICA components (r = 0.44, P < .001). Repeating the analysis with 10, 15, 25, 30, 35, and 40 components, we found that the correlation remained but was weaker (r = 0.35-0.41).
  
  
  CONCLUSIONS
  There is a significant but not complete correspondence between the results provided by ICA and ROI-based analysis of resting-state data.
authors: Neuroradiology Unit, Fondazione IRCCS Istituto Neurologico "Carlo Besta," Milan, Italy. cristina.rosazza@istituto-besta.it
authors: C
authors: C
authors: Rosazza
authors: L
authors: L
authors: Minati
authors: F
authors: F
authors: Ghielmetti
authors: M L
authors: ML
authors: Mandelli
authors: M G
authors: MG
authors: Bruzzone
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009415:Nerve Net / Q000502:physiology*; D009434:Neural Pathways / Q000502:physiology; D025341:Principal Component Analysis; D015203:Reproducibility of Results; D012146:Rest / Q000502:physiology*; D012680:Sensitivity and Specificity; D013223:Statistics as Topic