I have a question with regards to the afni command 3dRSFC. That is, FATCAT claims that with the command 3dRSFC one can determine the FA between two GM ROI (from fMRI data). However, my question is, how does it obtain the FA from the fMRI data alone? Shouldn’t it be combine with the WM regions as well in order to output the FA values?


I think there is some confusion. However, 3dRSFC, a time series-based function, doesn’t calculate FA, which is a DTI-based property.

Could you please point out where it is stated that 3dRSFC can do anything with FA values?