Hello,

I am a newbie with gPPI so I apologize if this is trivial. Consider two seed regions of interests (e.g. two spheres in two different parts of the brain). I run gPPI for both of them. I have noticed that the value reported in the seed1 t-results at location of seed2, is different from the value reported in seed2 results at location seed1: i.e. the gPPI results are not symmetric. Since I am trying to build a connectivity (adjacency) matrix between multiple ROIs, the adjacency matrix is not symmetric and I am not sure how to proceed with graph theoretical measures.

Is there an error in my analysis or is it correct that the results are not symmetric? The top triangle of the adjacency matrix is strongly correlated with the bottom triangle, but since they are not identical I am not sure which value to consider as "task connectivity" link weight between the two ROIs.

Thank you!
Enrico