I have run a group analysis on RSN data and am trying to correctly
interpret the output. I have specified 4 contrasts. How are the subject mode
effect sizes calculated? Is their a technical report that discusses this? I
am mainly interested in determining what is the cause of specific subject
being an outlier for a component. I.e. is it a difference in this specific
subject from the averaged spatial map or from the averaged time-course?
Also, I believe the subject mode effect size has been referred to as a
vector of spatial-temporal subject specific differences. This slightly
confuses me since with multi-session temporal concatenation mode, I thought
the time-course was assumed to be variable between subjects (unlike with
tensor ICA). I don't understand the utility of an "averaged time-course" or
the contribution of a timecourse to a subject's effect size, given that the
subject's timecourse is not assumed to be consistent with other subjects'
timecourses during the decomposition.
More broadly, if the t-tests turn up a difference between groups is there
information about where this difference is spatially? Are these differences
calculated similarly to randomise? Is it possible to show the location of
between group differences in melodic or is it best to run the groups
separatly and then compare the z-maps to find spatial-specific differences
between groups? Sorry for so many questions!
Chris Bell
|