Using the non-parametric Fieldtrip sourcestatistics test on the TF files calculated using the method from the Omega tutorial
Start working with only the process Test > Permutation test: Independent, Files A=15 files (one for each patient), Files B=14 files (one for each control subject).
The same applies when I try with the permutation tests.
What do you mean by "the same"? The is no problem of significant clusters if you don't use clusters.
When you display the results of the test, you can edit the p-value threshold used to assess significance. Set it the threshold to something high (0.9 or 1), with no correction for multiple comparison, and you will see the value of the t-statistic for all the vertices. Play with this threshold to explore the significance of your results.
Most likely, you just don't have any significant effect between your two groups for thee measure you computed. Maybe the hypothesis or the processing pipeline are to blame instead of the statistical test.
I get the same results even though I use all 29 subjects, as opposed to those 6 sample subjects I used to test out the protocol. I don't think it's a problem of sample size
29 is a small sample size.
Based on what you suggested, my guess would be to compute the sources, project to default anatomy, extract the scout time series
Do not project to the template. Select directly the source files in the Process1 box, run the process "Power spectrum density" with the option "Use scouts" selected.
I'm not sure if there's a bug in the program, but extracting the Magnitude from the complex values does not make a difference when I test the extracted files.
It should not make much difference with non-parametric statistics. But it would with parametric statistics.
I recently removed this warning about using the magnitude vs the power when using non-parametric tests.
On a related note, how would I extract the power values for the scout so I can correlate with behavioural measures?
There are no tools for this in Brainstorm yet. You would need to read the values directly from the files in a script and compute the correlations yourself.