Hi Paul,
Thank you again for your helpful reply!
Rick says here that high-pass filtering isn't an issue, it's more low-pass filtering that eats up most DOF.
But for the purposes of RSFC, is doing only high-pass filtering ok, or do you still advise against it? You mentioned that I cannot bandpass my time series, but I'm not sure if you meant doing both low- and high-pass filtering.
In the case of fmriprep, high-pass filtering is performed by including cosine regressors generated with discrete cosine basis, with a cutoff 128s during the denoising step. So, if I denoised using this high-pass filter, would it be ok to run 3dRSFC on the high-pass filtered data?