Fig. 1: Rapid and reliable connectome evaluation with the ReAl-LiFE algorithm.
a, Schematic of the LiFE model. O(w), objective function value. b, Schematic of the GPU-accelerated LiFE algorithm. c, Left: speedups as a function of the number of fibers Nf for datasets H (yellow), I (black) and S (blue). The x axes are shown in log scale. Middle: speedups as a function of the number of voxels Nv in each diffusion MRI volume. Right: speedups as a function of the number of gradient directions Nθ for each diffusion MRI scan. Filled circles, connectome sizes tested. Solid lines, logarithmic fit. Dashed open circles indicate points excluded from the logarithmic fit. d, Heatmaps showing within-participant variability (Vw) against between-participant variability (Vb) across n = 561 connections from five participants’ test–retest data, following pruning with the LiFE algorithm (top) and the ReAl-LiFE algorithm (bottom). Dashed diagonal line, line of equality. One-sided Wilcoxon signed-rank test, P = 0.119 (top), ***P < 0.001 (bottom). e, Vector plots demonstrating the improvement in reliability, relative to the unpruned connectome, following pruning with each of four different methods. Each plot shows change in within-participant variability (ΔVw) against change in between-participant variability (ΔVb) following pruning with LiFE (top left), ReAl-LiFE (bottom left), SIFT2 (top right) and COMMIT2 (bottom right). Each vector corresponds to one of the 561 connections evaluated. f, Reliability matrix, whose (i, j)th entry indicates the reliability measure (ϕ = Vb/(Vb + Vw)) of each pair of (n = 561) intra-hemispheric connections between regions i and j. Deeper shades indicate connections with higher test–retest reliability. R, right; L, left. g, Average reliability (ϕ) across all connections (n = 561) after pruning with LiFE, ReAl-LiFE, SIFT2 and COMMIT2. Center line, median; box limits, upper and lower quartiles; whiskers, 1.5× interquartile range; points, outliers. One-sided Wilcoxon signed-rank test: LiFE versus ReAl-LiFE, ***P < 0.001; ReAl-LiFE versus COMMIT2, **P < 0.01. h, Exemplar tracts corresponding to two connections with high consistency. i, Exemplar tracts corresponding to two connections with low consistency.
