Hi Konstantinos,

I assume that you've already estimated your first level task model. If this is the case, running the command without line 59 SPM=spm_estimate_ppi... should solve the issue of it running.

PPPI(P) will estimate the model and contrasts for you.

However, I don't believe that the PPPI toolbox can handle .gz VOI files. Could you change this file to simply be a .nii file and run the script again?

If you get the estimation failure again, please copy and past the full matlab window output along with stats_right_hippocampus_session1_cond_PPI_regressors.mat file.

I suspect the issue maybe that the stats_right_hippocampus_session1_cond_PPI_regressors.mat file is empty and thus there are no PPI columns in the model. So the model estimates, but the contrasts can't find the PPI columns.

Best,
Donald