We used the data set with "sfnw* included in the file ADHD200_AAL_TCs. We found that in some time series have an obvious increasing or decreasing trend. 
We therefore detrended these time series. Should we do this? 


Another issue is about thepower below 0.009Hz. We used both FFT and PMTM codes in matlab. It is strange that in voxel level, there is no power below 0.01Hz (or 0.009Hz in the current data set), but when we looked at the brain region time series which are the average of the voxel time series in the ROI, there are obvious powers below 0.009Hz. We are wondered whether this is due to the problem of filter procedure or the the FFT algorithm.