Dear Prerona,
The original PPI paper clarifies an ambiguity in the interpretation of PPI results. For each of your PPI analyses, it could be that the seed is contributing to activity in the target region. It could alternatively be that the seed is modulating the sensitivity of the target region to the task. A previous post in the mailing list suggested another way of looking at this. The seed could be positively contributing to activity in the target, or alternatively the target could be negatively contributing to activity in the seed.
As you say, plotting the interaction would be a good idea.
Best,
Peter.
-----Original Message-----
From: SPM (Statistical Parametric Mapping) [mailto:[log in to unmask]] On Behalf Of Prerona Mukherjee
Sent: 04 August 2014 20:41
To: [log in to unmask]
Subject: [SPM] PPI connectivity from region A as seed to region B + reverse direction
Hi
I have run a PPI analysis and I am trying to interpret the results. I have significant connectivity difference between two groups from region A as seed to a region B. I have also run an analysis from region B as a seed and I get a significant group difference in a region close to A. Can I interpret this as both regions are contributing to each other? Is there any way I can explore this further, or better understand what is going on and visualise or demonstrate this? I would be grateful for any advice
Sincerely
Prerona
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