Hi all,

I am participating in a resting-state fMRI study. Before group ICA, I would like to remove some non-interest independent components for each subject (5 runs with 90 volumes each one), applying Melodic and fsl_regfilt. Each run has been preprocessed separately.

I am considering two options, for each subject:

A) Melodic for each run, obtain ICs and fsl_regfilt for each run 
    (5 times because there are 5 runs)

B) Melodic with a list of the 5 runs as input and obtain ICs.
    Then, apply fsl_regfilt to each run. For that, it is necessary to split melodic_mix in matrices of 90 rows (because each run has 90 volumes), i.e.
fsl_regfilt -i run1 -o run1_denoised -d melodic_mix_rows1to90 -f "1,2"
fsl_regfilt -i run2 -o run2_denoised -d melodic_mix_rows91to180 -f "1,5"
fsl_regfilt -i run3 -o run3_denoised -d melodic_mix_rows181to270 -f "8,2"
fsl_regfilt -i run4 -o run4_denoised -d melodic_mix_rows271to360 -f "7,2"
fsl_regfilt -i run5 -o run5_denoised -d melodic_mix_rows361to450 -f "9,2"

I prefer option B because it requires less workload to identify good or bad components, and also because maybe one run is not enough for ICA.

Please, could you tell me if option B is correct?

Thank you very much,

All the best,

Úrsula