Fig. 10.

Twin/non-twin WM tract similarity using 72 subject pairs per group. Correlations are performed on normalised tract density maps with a threshold of 0.5%. μ is the group median across tracts and subjects and $\sigma$ is the standard deviation. A Kruskal-Wallis test is used to determine whether the groups come from the same median: χ² = ​122.3, p ​= ​2 ​× ​10^-26, mean ranks ​= ​222.6 (monozygotic), 145.1 (dizygotic), 134.4 (non-twin siblings) and 69.9 (unrelated).