Dear all,
I have a sort of basic question about group ICA design. I wish to run ICA on two groups (control vs patients). We have the following options concerning the group analysis:
1) do the initial ICA definition on all subjects regardless of group, and then dual regression on each subject in the analysis.
2) do the ICA definition only on the control group, and then dual regression on the subjects from both groups. This will decrease false negatives.
3) do the ICA definition on a large control group (that does not include the control subjects in the subsequent analysis) and then dual regression on all subjects that will be part of the analysis.
4) do ICA on the patients alone and the control group alone, and then do dual regression for each group separetely and carry the second level analysis on matching networks.
4 is probably the least preferred option, as it will introduce too much bias and false positives. 3 to me seems the best, but I am not sure if it is valid to do the initial ICA on subjects outside the main analysis.
I would greatly appreciate your help on this issue.
Best regards,
George
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