Hi SPM experts,
I have a multi-condition multi-session experiment, in which 18 conditions are presented in each of 8 scan sessions. In my gPPI setup, the resultant SPM.Vbeta shows for each session 43 regressors: 18 condition, 18 PPI, 1 seed, 6 motion regressors. My gPPI ran through w/o error, but at the very last there is a sentence saying "PPI contrasts were not estimated for some reason".
I wonder if I can manually set up the contrast as a separate step using the regular SPM contrast manager? I am interested in contrasting the PPI from the first 3 conditions with the 4-6th conditions, i.e., contrast manager [zeros(18,1), 1 1 1, -1 -1 -1].
Could someone let me know if this is the right way? Or if anything wrong with it, please teach me how I should set it up.
Thank you in advance!!
Best,
Frances
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