Dear SPMers,
I are running an fMRI event related design with two motion conditions
Radial (A) & Translational (B) with Random motion as an implicit baseline
condition. I have modelled the design with canonical HRFs, temporal and
dispersion derivatives. I am interested in assessing the difference in
effect sizes for the two motion conditions in a priori ROIs. Which of the
following contrast is better for picking up the voxels for calculating
the effect sizes?
The contrasts are as follows
Average condition F contrast
A_HRF A_dt A_dw B_HRF B_dt B_dw
[1 0 0 1 0 0
0 1 0 0 1 0
0 0 1 0 0 1]
Main Effect F contrast
A_HRF A_dt A_dw B_HRF B_dt B_dw
[1 0 0 0 0 0
0 1 0 0 0 0
0 0 1 0 0 0
0 0 0 1 0 0
0 0 0 0 1 0
0 0 0 0 0 1]
Thank you very much, looking forward for your reply.
Regards,
Mariam
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