Dear SPMers,
I'm trying to do the PPI analysis. After reading the PPI section of SPM manual, I have a few questions about the correction issue.
1) In the manual, FWE correction was applied in the extracting VOIs step, and after the PPI analysis no correction was applied to the result. Why it needs to use the corrected contrast to get the VOI. In other words, can I use the uncorrected contrast to get the VOIs, and corrected it in group analysis at the second level?
2) I noticed that PPI analysis is usually applied to block design. If I want to apply it to event-related design, would that be OK to do it? although it will have more fasle negative results ...
Thanks!
Best regards, Jing
|