Dear SPM Experts,
A reviewer asked how much variance a contrast can explain an activity in a ROI. I didn't find any information about that in the manual nor in the SPM list...
I wonder if the method to do this with SPM (see below) is OK and/or if there is a better way to do it.
There are 21 subjects * 4 sessions * 2 conditions (N & D)
for each session, the 1st eigenvalue for that ROI is extracted with the 'eigenvariate' button
It returns the % variance explained by that contrast (xY.s(1)*100/sum (xY.s))
then I calculate the mean % for the group.
All comments or references will be helpful,
regards,
Isabelle
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