Dear Experts,

In the 6_singlesubjectRSFC.sh file,
****
## 3. Z-transform correlations       
echo Z-transforming correlations for seed ${seed_name}
3dcalc -a ${RSFC_dir}/${seed_name}_corr.nii.gz -expr 'log((a+1)/(a-1))/2' -prefix ${RSFC_dir}/${seed_name}_Z.nii.gz
****
This step applies Fisher Transformation, and if I'm not wrong the definition of this transformation is log((1+a)/(1-a))/2, why (a-1) used instead?

Thank you very much.



Regards,

Ali Bayram

Hi Ali,

Mathematically, yes, your are right. But, in practice, it gets same outputs. It's a trick about using 3dcalc, which gives you the real number if the true is a complex number, the real part of the complex number. Better to change it to the correct form to avoid the confusion. Hope this explaination clear.

Best, XN.

Originally posted by Ali Bayram:

Hi Xi-Nian,
Thanks for the explanation.
Regards,
Ali