Dear Alfonso,

Thank you for your quick reply and the detailed explanation. 

Regarding the usage of REX I encountered the problem that if I start it from the command line that it gives error message when I want to save the output data, presumably because it does not have an output folder defined (and doesn't use the current folder either). This is no problem if I start REX from the seed-to voxel explorer with 'Explore Clusters'

This would be the error message:

Reference to non-existent field 'output_folder'.
Error in rex>rex_do (line 789)
name_dat=fullfile(params.output_folder,[ROInames{rr},'.rex.data.mat']);
Error in rex>rex_gui (line 444)
[data.params.ROIdata,data.params.ROInames,data.params.ROIinfo.basis,data.params.ROIinfo.voxels,data.params.ROIinfo.files,data.params.ROIinfo.select,data.params.ROIinfo.trans]=rex_do(data,~dat
Error while evaluating uicontrol Callback

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Besides just three quick follow up questions.

1) I create my DMN mask based on the results of the whole sample. Do I have to orthogonalize my covariate in the Setup.2nd level covariates tab two the 'All' covariate or does this already avoid the circularity problem?

2) After masking is it 'allowed' to use lower height and extend thresholds? Do you have any recommendation for this?

3) With REX, I did not extract the data with the default mode network (DMN) mask but with a mask of only the significant clusters from my DMN-masked covariate analysis in SPM. Would this bias my results?

Best,
Julia