Dear Donald, dear gPPI users,

I have successfully performed a gPPI analysis on my data a few months ago. I copied and pasted the results of the whole brain analysis on an excel sheet, and performed several beta extractions using Marsbar. I then re-opened the same second-level SPM.mat two weeks ago and found different results (i.e., the activated regions were relatively the same, but cluster size and significance were modified). Even worse, I re-launched the exact same gPPI and second level scripts to try and reproduce either the first or second set of data, and found... a third set of data.

Do you have any idea where these discrepancies could come from? For example, I was wondering if the gPPI could have modified the first level SPM.mat of the participants?

I would be very thankful for any input or help.

Kind regards,

Fabien Carruzzo