I am a statistician supporting some fMRI work and am trying to work out what
SPM offers in the way of the second stage grouped analysis. Please could
someone answer my following questions. Thanks
1) Will the second stage GLM allow a hierarchical ANOVA or mixed model for a
cross-over design, where some comparisons are between fMRI sessions, but
within subject and others are between subjects? For example, population
differences will be assessed at the between subject level and treatment
differences could be assessed at the within subject level. Also does the
software allow multiway ANOVAs and analysis of covariance at the second
stage GLM
2) From the second stage analysis is it possible to obtain both within and
between subject estimates of variability on a voxel by voxel basis and use
these estimates in calculations out side of SPM?
3) Similarly is it possible to obtain treatment differences on a voxel by
voxel basis from the analysis to use outside of SPM?
4) From the second stage analysis that is adjusted for multiple comparisons
and clustering, is it possible to work out what the equivalent unadjusted
threshold p-value is on a voxel by voxel basis and is it the same for all
voxels?
Thanks for our help
Trevor Smart
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