Hi Brendan

That difference / asymmetry in the connectivity values is a property of the type of analysis performed. In particular, in gPPI the task-related connectivity between regions A and B (the value at the position Z(i,j)) is different from the task-related connectivity between regions B and A (the value at the position Z(j,i)). The proper interpretation of that difference is a matter of debate, so often times when people are not interested in the directionality of the effects they would compute just the average of the two directions to compute a single "task-related connectivity" effect for each pair of ROIs.

Hope this helps

Alfonso

Originally posted by Brendan Angelo:

Hi experts,

In this project I want to extract the first level connectivity values for each subject from a gPPI analysis, and have found the appropriate file (resultsROI_Subject###_Condition###.mat). However, upon viewing the matrix within the file, the connectivity values differ across the NaN line of the ROI-to-ROI matrix. I searched through the forum and documentation to see if there is a description of what the difference between values are and what are the "true" values to extract, but haven't had any luck.

Can anyone point me to the correct values to use for a regression analysis outside of CONN? I've attached a converted sheet of one subject's output for reference. 

Thank you!

Sincerely,

Brendan