Open mgogniat opened 6 years ago
Just following up on this, thanks!
It would be helpful if the tools could provide the result files of each step, such as the files of correlation between any two variables (X-Y, X-M, and M-Y), rather than the files of mediation result. Thanks in advance.
Hi @mgogniat ,
The indirect effect (SobelZ) from the voxel-wise mediation are in the output directory. The intermediate steps are calculated internally. If you need each step, I recommend calculating them individually using step1-voxel-regress. For instance, if the image is the 'M' variable:
IVAR.csv -> Single column of independent (left) variable (such as diagnosis) DVAR.csv -> Single column of dependent (right) variable (such as cognitive performance score) IVARandDVAR.csv -> Two columns of containing IVAR and DVAR
M ~ X + b (Step 1): tfce_mediation step1-voxel-regress -i IVAR.csv covars.csv
-> {neg}tstats_con1* image is the effect of path A
Y ~ X + M + b (Step 2): tfce_mediation step1-voxel-regress -i IVARandDVAR.csv covars.csv
-> {neg}tstats_con2* image is the effect of path B Note: the M (image) variable and Y (dependent) variable are switched here. That's ok since the tstat is equivalent either way.
Indirect effect: tfce_mediation step1-voxel-mediation -i IVAR.csv DVAR.csv -c covars -m M
If steps 1, 2, and the indirect effect are all significant, then the mediation effect is valid.
@WeiCheng88 The TFCE transformed T-stats can be calculated as above. The correlations/betas would not be informative because of TFCE.
Hello,
I'm wondering if you could provide me some information on where the output files from each step in the process of completing a voxel-wise mediation can be found (i.e., under what directories?).
Thanks,
Marissa