Dear FSL Experts,
I am conducting a TBSS analysis on FA, MD, AD and RD and plan to use TFCE. The study consists of two groups (control = 11 and patient = 19) who differ significantly in IQ. Therefore, I wanted conduct the analysis controlling for IQ and would be extremely grateful for help in generating the appropriate design.con and design.mat files.
I have looked through the forum for answers and have drafted the following:
design.con
/NumWaves 4
/NumContrasts 2
/PPheights 1 1
/Matrix
1 -1 0 0
-1 1 0 0
Can you please tell me whether this design.con file is correct?
design.mat
/NumWaves 4
/NumPoints 30
/PPheights 86 86
/Matrix
1 0 -8.4 0
1 0 12.6 0
1 0 16.6 0
1 0 0 0
1 0 2.6 0
1 0 -22.4 0
1 0 -1.4 0
1 0 8.6 0
1 0 -3.4 0
1 0 -4.4 0
1 0 -0.4 0
0 1 0 35.7
0 1 0 15.7
0 1 0 10.7
0 1 0 8.7
0 1 0 -5.3
0 1 0 -40.3
0 1 0 22.7
0 1 0 16.7
0 1 0 -11.3
0 1 0 -15.3
0 1 0 -13.3
0 1 0 -1.3
0 1 0 -6.3
0 1 0 8.7
0 1 0 1.7
0 1 0 29.7
0 1 0 -7.3
0 1 0 -50.3
0 1 0 0
Can you please tell me whether this design.mat file is correct?
Also, I wanted to double check that the PPheights are the difference between the most negative and most positive demeaned IQ for the entire sample, and the IQ needs to be demeaned separately for control and patient groups.
Finally, in order to run this would the procedure the same as that indicated on the main TBSS documentation page, just using the above for the for the design.mat and design.con files below:
randomise -i all_FA_skeletonised -o tbss -m mean_FA_skeleton_mask -d design.mat -t design.con -n 500 --T2 -V
Thanks in advance for your help!
Roger
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