Reproducibility of Single-Subject Functional Connectivity Measurements

Intersession reproducibility. Mean difference in Fisher-transformed correlations across 2016 pairs of 64 regions of interest between samples of scans obtained in different sessions. Error bars show SDs across 100 groupings of ≤10 scans.

Intersubject reproducibility. A, Mean difference in Fisher-transformed correlations across 2016 pairs of 64 regions of interest between samples of scans obtained in different subjects. The curve showing 0.25 / sqrt(n) is superimposed. Error bars represent SDs across groups of subjects. B, Difference in correlation for 2016 pairs of 64 regions for 2 groups of 20 resting (eyes open) scans. C, Difference in correlation for 36 scans from different subjects by using 5 minutes of imaging data, compared with 50 resting scans from 1 subject.

Effect of region-of-interest choice on reproducibility. A, Mean difference in correlation for pairs of regions of interest defined by the AAL atlas and different subsets of the 64 coordinates chosen for the analysis within resting-state scans from a single individual (intersession). Error bars show SDs across 100 groups of scans. B, Mean differences in correlations for the same pairs of regions of interest for group results. Error bars show SDs across 100 groups of subjects for each number of scans averaged.

Imaging time required to distinguish an individual's functional connectivity fingerprint from the population. A, Interindividual, intersession, and intrasession reproducibility shows only small differences and similar improvements with more imaging time used to construct measurements. B, Mean differences in correlations within the group and between the individual and the group with increased number of scans averaged. The black line shows α / sqrt(n) to project expected reproducibility if increasing numbers of group subjects are used. The individual and group values diverge with increased imaging time. C, Number of individual pairs of regions of interest, which are significantly different between the individual and the group over 95% of n resting scan samples selected from the individual's results.