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Dear fsl list,

i have 4 different groups to analize FA index. I performed a Glm matrix:

/Matrix
1.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	
1.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	
1.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	
1.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	
1.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	
1.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	
1.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	
1.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	
1.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	
1.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	
1.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	
1.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	
1.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	
1.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	
1.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	
1.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	
1.000000e+00	0.000000e+00	0.000000e+00	0.000000e+00	
0.000000e+00	1.000000e+00	0.000000e+00	0.000000e+00	
0.000000e+00	1.000000e+00	0.000000e+00	0.000000e+00	
0.000000e+00	1.000000e+00	0.000000e+00	0.000000e+00	
0.000000e+00	1.000000e+00	0.000000e+00	0.000000e+00	
0.000000e+00	1.000000e+00	0.000000e+00	0.000000e+00	
0.000000e+00	1.000000e+00	0.000000e+00	0.000000e+00	
0.000000e+00	1.000000e+00	0.000000e+00	0.000000e+00	
0.000000e+00	1.000000e+00	0.000000e+00	0.000000e+00	
0.000000e+00	1.000000e+00	0.000000e+00	0.000000e+00	
0.000000e+00	1.000000e+00	0.000000e+00	0.000000e+00	
0.000000e+00	1.000000e+00	0.000000e+00	0.000000e+00	
0.000000e+00	1.000000e+00	0.000000e+00	0.000000e+00	
0.000000e+00	1.000000e+00	0.000000e+00	0.000000e+00	
0.000000e+00	1.000000e+00	0.000000e+00	0.000000e+00	
0.000000e+00	1.000000e+00	0.000000e+00	0.000000e+00	
0.000000e+00	1.000000e+00	0.000000e+00	0.000000e+00	
0.000000e+00	1.000000e+00	0.000000e+00	0.000000e+00	
0.000000e+00	1.000000e+00	0.000000e+00	0.000000e+00	
0.000000e+00	0.000000e+00	1.000000e+00	0.000000e+00	
0.000000e+00	0.000000e+00	1.000000e+00	0.000000e+00	
0.000000e+00	0.000000e+00	1.000000e+00	0.000000e+00	
0.000000e+00	0.000000e+00	1.000000e+00	0.000000e+00	
0.000000e+00	0.000000e+00	1.000000e+00	0.000000e+00	
0.000000e+00	0.000000e+00	1.000000e+00	0.000000e+00	
0.000000e+00	0.000000e+00	1.000000e+00	0.000000e+00	
0.000000e+00	0.000000e+00	1.000000e+00	0.000000e+00	
0.000000e+00	0.000000e+00	1.000000e+00	0.000000e+00	
0.000000e+00	0.000000e+00	1.000000e+00	0.000000e+00	
0.000000e+00	0.000000e+00	1.000000e+00	0.000000e+00	
0.000000e+00	0.000000e+00	1.000000e+00	0.000000e+00	
0.000000e+00	0.000000e+00	1.000000e+00	0.000000e+00	
0.000000e+00	0.000000e+00	1.000000e+00	0.000000e+00	
0.000000e+00	0.000000e+00	1.000000e+00	0.000000e+00	
0.000000e+00	0.000000e+00	1.000000e+00	0.000000e+00	
0.000000e+00	0.000000e+00	1.000000e+00	0.000000e+00	
0.000000e+00	0.000000e+00	1.000000e+00	0.000000e+00	
0.000000e+00	0.000000e+00	1.000000e+00	0.000000e+00	
0.000000e+00	0.000000e+00	0.000000e+00	1.000000e+00	
0.000000e+00	0.000000e+00	0.000000e+00	1.000000e+00	
0.000000e+00	0.000000e+00	0.000000e+00	1.000000e+00	
0.000000e+00	0.000000e+00	0.000000e+00	1.000000e+00	
0.000000e+00	0.000000e+00	0.000000e+00	1.000000e+00	
0.000000e+00	0.000000e+00	0.000000e+00	1.000000e+00	
0.000000e+00	0.000000e+00	0.000000e+00	1.000000e+00	
0.000000e+00	0.000000e+00	0.000000e+00	1.000000e+00	
0.000000e+00	0.000000e+00	0.000000e+00	1.000000e+00	
0.000000e+00	0.000000e+00	0.000000e+00	1.000000e+00	
0.000000e+00	0.000000e+00	0.000000e+00	1.000000e+00	
0.000000e+00	0.000000e+00	0.000000e+00	1.000000e+00	
0.000000e+00	0.000000e+00	0.000000e+00	1.000000e+00	
0.000000e+00	0.000000e+00	0.000000e+00	1.000000e+00	
0.000000e+00	0.000000e+00	0.000000e+00	1.000000e+00	

And their contrasts:

/Matrix
1.000000e+00 0.000000e+00 -1.000000e+00 0.000000e+00 
-1.000000e+00 0.000000e+00 1.000000e+00 0.000000e+00 
1.000000e+00 0.000000e+00 0.000000e+00 -1.000000e+00 
-1.000000e+00 0.000000e+00 0.000000e+00 1.000000e+00 
1.000000e+00 -1.000000e+00 0.000000e+00 0.000000e+00 
-1.000000e+00 1.000000e+00 0.000000e+00 0.000000e+00 
0.000000e+00 0.000000e+00 1.000000e+00 -1.000000e+00 
0.000000e+00 0.000000e+00 -1.000000e+00 1.000000e+00 
0.000000e+00 -1.000000e+00 1.000000e+00 0.000000e+00 
0.000000e+00 1.000000e+00 -1.000000e+00 0.000000e+00 
0.000000e+00 -1.000000e+00 0.000000e+00 1.000000e+00 
0.000000e+00 1.000000e+00 0.000000e+00 -1.000000e+00 


There are two contrast with significant results when i run randomise:

randomise -i all_FA_skeletonised.nii -m mean_FA_skeleton_mask.nii -o resultados_TBSS -d matriz.mat -t matriz.con -n 5000 --T2 -V

However this procedure has been criticized because there is not a previous overall of results and i am wondering if i first have to do a F-tests:

http://fsl.fmrib.ox.ac.uk/fsl/fslwiki/FEAT/UserGuide#F-Tests

I have to do a F-test first? In that case, what will indicate these results:

- C1: Group A        1  0  0  0

(if i found results here, e.g. cluster --in=resultados_FA_mean_FA_skeleton_mask_tfce_corrp_tstat1.nii.gz --thresh=0.95), would this indicating Group A differ from other groups and then i could finally do my first procedure? Or it is not necessary this first F-test analysis?

Thanks in advance,

Patricia.