Toward reliable characterization of functional homogeneity in the functional connectome

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• Xi-Nian Zuo, Research Professor, Institute of Psychology, Chinese Academy of Sciences, Beijing
• Tuesday 06 November 2012, 11:00-12:00
• BCNI seminar room, Sir William Hardy Building, Downing Site.

If you have a question about this talk, please contact Mikail Rubinov.

While researchers have extensively characterized functional connectivity between brain regions, the characterization of functional homogeneity within a region of the brain connectome is in early stages of development. Several functional homogeneity measures were proposed previously, among which regional homogeneity (ReHo) was most widely used as a measure to characterize functional homogeneity of resting state fMRI (R-fMRI) signals within a small region. Despite a burgeoning literature on ReHo in the field of neuroimaging brain disorders, its test-retest (TRT) reliability remains unestablished. Using two sets of public R-fMRI TRT data, we systematically evaluated the ReHo’s TRT reliability and further investigated the various factors influencing its reliability and found: 1) nuisance (head motion, white matter, cerebrospinal fluid) correction of R-fMRI timeseries can significantly improve the TRT reliability of ReHo while additional removal of global brain signal reduces its reliability, 2) Spatial smoothing of R-fMRI timeseries artificially enhances ReHo intensity and influences its reliability, 3) surface-based R-fMRI computation largely improves the TRT reliability of ReHo, 4) a scan duration of 5 minutes can achieve reliable estimates of ReHo, and 5) fast sampling rates of R-fMRI dramatically increase the reliability of ReHo. Inspired by these findings and seeking a highly reliable approach to exploratory analysis of the human functional connectome, we established an R-fMRI pipeline to conduct ReHo computations in both 3-dimensions (volume) and 2-dimensions (surface).

This talk is part of the Brain Mapping Unit Networks Meeting and the Cambridge Connectome Consortium series.

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• BCNI seminar room, Sir William Hardy Building, Downing Site
• Brain Mapping Unit Networks Meeting and the Cambridge Connectome Consortium
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