Hi,
a question on how to report interaction results (eg, Group by Time by Condition) from whole brain anovas.
I have used the afni 3dAnovas several times, but often, since we have uneven number of subjects in each group in our studies, we run a whole brain anova using a home-grown whole-brain Anova program and then we run t-tests in AFNI to compare the groups on the various task conditions to further explore the interaction effects, and finally we apply alphaSim tresholding to the cluster results.
We then report only the clusters that are significant from the t-tests and corresponds to the significant clusters we saw in the whole brain interaction F map. All the significant clusters that we report in tables have the same cluster thresholding value based on alphasim.
Is this a good approach? or am I missing something?
Reviewers of our paper (who seem to use SPM) are saying that t-tests should be not whole brain but should be done only on clusters that were significant in the interaction map and different p values should be given for every cluster. Thanks,
AP