Dear SPM5 experts
I have a very blunt and basic question considering the extraction of
VOI-data in SPM5.
What I want to do is this: extract the data for a pre-defined VOI from each
subject, and use these values to construct my PPI-vector.
The problem which I am encountering is that I can only extract VOI-values
for clusters which are active (singnifically) in a specific subject. The
point is that I use a pre-defined VOI, and I would like to get the data for
each subject. This question has already been posted in this forum, the
suggested solution for this problem was to either include only those
subjects in the VOI-analysis who show significant activation in the
VOI-region, or to set a more liberal p-value.
I am in doubt considering the exact procedure one should use; is it valid to
use an extrem liberal p-value? Are the results obtained in that manner still
utilizable in order to perform a PPI-analysis?
Any help would be greatly appreciated,