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A between group tbss_sym FA analysis revealed just a single cluster (made of 15 significant voxels) for L>R for experts (EXP) vs controls (CON); contrast C2 below for corrp_tstat2. The max x, y and z mm coordinates were -21, -56, 39, C1 was ns for L>R. By contrast , the R>L test showed C1 CON>EXP, corrp_tstat1, but at the same coordinates as C1 from the L>R test (-21, -56, 39). The C2 R>L (Exp>CON) test was ns. The coordinates -21, 56, 39 identified as the inferior longitudinal fasciculus (posterior portion) and the posterior part of the anterior thalamic radiation by the JHU white matter tractography atlas. It is reasonable to expect some FA difference between experts and controls but it seemed strange that the difference would occur at the same coordinates. I thought I could have made an error multiplying the randomize L>G input by -1 to arrive at the R - L input for randomize. But I also tried a separate analysis deriving the R - L by multiplying the contrast by negative 1 with the same results. Does this seem an appropriate result??? All tests were run at 5000 permutations, cluster reports peak coordinates (following http://fsl.fmrib.ox.ac.uk/fsl/fslwiki/Randomise/UserGuide#Getting_Cluster_and_Peak_Information_from_Randomise_Output) agreed with visual inspection in fslview. Evs and Contrast are below: there were not correlations between significant FA differences and age or gender (age and gender were demeaned, age-mean(age)) Group EV1 EV2 EV3 EV4 CON EXP Age Gender 1 1 0 -1.94 -0.22 1 1 0 26.06 -0.22 1 1 0 -4.94 -0.22 1 1 0 -2.94 -0.22 1 1 0 -4.94 -0.22 1 1 0 -5.94 -0.22 1 1 0 -3.94 -0.22 1 1 0 -5.94 -0.22 1 1 0 -3.94 -0.22 1 0 1 3.06 -0.22 1 0 1 3.06 -0.22 1 0 1 1.06 -0.22 1 0 1 2.06 -0.22 1 0 1 -0.94 -0.22 1 0 1 0.06 0.78 1 0 1 -0.94 0.78 1 0 1 -0.94 0.78 1 0 1 2.06 0.78 Contrasts EV1 EV2 EV3 EV4 C1 CON > EXP 1 -1 0 0 C2 EXP> CON -1 1 0 0 Pos eff age 0 0 1 0 Neg eff age 0 0 -1 0 Eff of gender 0 0 0 1