Hi, I am following the steps to preprocess a bold signal and I would like to know whether an additional column should be added in the nuisance file to correct the signal from its trend or if the detrend is already carried out in the previous steps.
Thank you for the help,
Giulia.
Giulia, hi!
Baseline and linear trend are automatically added to the GLM, so there is no need to add trend to the nuisance file. If you are using process_conc to process a set of concatenated bold files, a separate baseline and linear trend regressor will be added for each of the bold files. The estimates for baseline and trend regressors are also present in the file with the beta coefficients, if you would like to inspect them.
With kind regards,
Grega