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Demonstrate Regional Variation in the Impact of Motion on the BOLD Signal (Figures 1, 2, S1, S2, S3)
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All datasets |
High motion datasets exhibited more pronounced negative motion-BOLD relationships (esp. prefrontal areas).
Low motion datasets exhibited more pronounced positive motion-BOLD relationships (esp. primary and supplementary motor areas).
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After applying the individual-level motion correction strategies on the functional data (after realignment), calculate the correlation between corrected BOLD signal and voxel-specific head motion.
Calculate the mean positive correlation and mean negative correlation as summary measures for each participant, and then perform paired t-test to compare strategies.
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Cambridge Adults (n = 158; 18 participants removed due to motion) |
Only ‘scrubbing’ (FD < 0.2mm) removed negative motion-BOLD relationships.
Positive motion-BOLD relationships tended to cluster in primary and supplementary motor areas and remained even after scrubbing, thus may reflect to motion-related neural activity.
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Calculate R-fMRI metrics after motion correction strategies, and then evaluate their correlation with motion across participants.
Wilcoxon signed-rank test were used to test the distribution of residual motion effects (absolute correlation) across motion correction strategies.
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Cambridge Adults (n = 158) |
None of the individual-level motion correction approaches successfully bypass the need for group-level correction for inter-individual differences in R-fMRI related to motion.
Z-standardization on subject-level maps reduced relationships between motion and inter-individual differences
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Cambridge Adults (n = 158) |
GSR introduced negative motion-BOLD relationships at individual level.
However, GSR was highly effective in removing inter-individual differences related to motion.
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Calculate R-fMRI metrics after motion correction strategies, then evaluate the test-retest reliability via intra-class correlation (ICC).
Wilcoxon signed-rank test were employed to compare the reliability across motion correction strategies.
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NYU TRT (high motion dataset [n = 11] vs. low motion dataset [n = 11]) |
Motion appears to reduced test-retest reliability for correlation-based metrics
Motion did artifactually increase the reliability of frequency-based metrics (ALFF >> fALFF); correction approaches reduced these increases.
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Plot the difference between FDvol and meansp FDvox as a function of meansp FDvox for all time points and all participants.
Plot the temporal mean of FDvol (mean FDvol) and temporal mean of meansp FDvox (mean [meansp FDvox]).
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Cambridge Adults (N = 176) |
Overall, there was high concordance among volume-based metrics of FD.
Failure to account for rotation can lead to substantial underestimation of FD.
The metric by Jenkinson et al. (2002) uniquely accounted for regional variation in motion.
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