I'm looking into running and interpreting PPI analyses, and I have a question. Rather than
a PPI analysis on the contrast between two conditions [1 -1 0], can one run a PPI analysis
looking at one condition versus baseline [1 0 0]? The former would give you differences
in functional connectivity with the seed VOI during Condition A versus Condition B. If I'm
interpreting things correctly, I believe that the latter would give you voxels in which the
functional connectivity with the seed VOI is greater for Condition A than the average
connectivity during the rest of the task (Condition B, Condition C, and resting blocks). Is
this interpretation correct?
From my quick search for existing studies using PPI analyses, I've only seen people use
contrasts of [1 -1]. Is there any reason that other contrasts aren't commonly used in the
literature (e.g, [1 0] or [1 -0.5 -0.5])?
Thanks in advance for your responses,
Greg Burgess, Ph.D.
Research Associate, Institute of Cognitive Science
University of Colorado - Boulder
Email: [log in to unmask]