Dear mailing list,
the problem that I am now facing seems to go in the opposite direction than the one I encounter in most of fmri experiments....
I analyzed by means of functional connectivity (with the PCC as seed region) a large number of healthy subjects (N>100) and I would like to do a one-sample statistic on the 100 functional connectivity maps of my subjects. The problem is related to thresholding the results of the one-sample T test.
Even if I choose a very low FWE corrected p-value (e.g., p=0.0000001 FWE corrected), I obtain an average functional connectivity map of my 100 subjects including most of the entire brain. Only if I arbitrarily choose a large T value (e.g., t=20 or 30) for thresholding, I obtain a nice average functional connectivity map (resembling the correct DMN pattern, as expected). If I do a one-sample t test on a subset of my subjects (e.g., on 30 subjects), I obtain almost the same average functional connectivity map by using a "normal" threshold of p=0.05 FWE-corrected.
Do you have some suggestions on how to threshold the one-sample results of my large dataset?
Kind regards and thanks for any advice
Paola
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