Dear experts,
I would like to ask the preprocessing questions on whether it is necessary to do detrending and filtering in rs-fMRI while calculating ReHo, ALFF, fALFF and Functional connectivity indexes. In other words, can I use the images just only with slice timing, realign, nuisance regression, normalization and smoothing steps (ARCWS) for ReHo (without smooth), ALFF, fALFF and Functional connectivity calculation?
Thanks for your help in advance.
Jing
Hi Jing,
Hi Jing,
For ALFF and fALFF, you don't need to do filtering in advance.
However, usually, for ReHo and Functional Connecvitiy, most people will do a filtering first.
Best,
Chao-Gan
Hi, Chao-Gan,
Hi, Chao-Gan,
Thank you for your reply.
From your reply, I would like to further check:
(1) whether detrending step is included in your referred "filtering" step.
(2) whether the calculated ReHo, ALFF, fALFF and FC values can be recognized without detrending and filtering steps.
Thank you very much for your help in advance!
Best,
Jing
Hi Jing,
Hi Jing,
1. Detrending could be either done in nuisance regression, where you have linear regressors. Or it can be done seperately in the "detrend" checkbox.
2. Basically, for all these methods, detrending will be performed. Though for ALFF and fALFF, filtering can be skipped.
Best,
Chao-Gan