I have a question concerning the "replicate over sessions" option in the
contrast manager in batch, SPM5.
I created a .mat file with contrast manager settings. My design matrix
contains 4 sessions, 2 trials per session. I also included time and
dispersion derivatives and realignment parameters as regressors. So I
have 12 columns per session in the design matrix. In contrast manager -
contrast sessions, it is possible to replicate a T-contrast ("Create per
session"). However, SPM adds resp. only two, four and six zeroes for the
other three sessions, instead of 12, 24 and 36 zeroes. I think this is
because in the SPM.mat file only two trials per session are saved and
the derivatives and rp-regressors are not taken into account.
Does anyone have experience with this finding? Is there a possibility to
correctly replicate per session (replicate defined contrast after 12
columns instead of 2)? Is there another way to change the number of
added zeroes? Or should I define all T-contrasts for each session
Thanks for your remarks.
Benedicte Descamps, MSc, PhD Student
Ghent University Hospital
Dep. of Neuroradiology, -1 K12 IB (5th August: DGL, room 022)
De Pintelaan 185
T +32 9 332 69 34
F +32 9 332 49 69