I am analyzing data from an fMRI experiment, 2 groups of subjects, 16 subjects per group. I have two within-subject factors, one with two levels the other with three, let’s call them A-B and 1-2-3, giving my design matrix at the first level 6 columns, A1, A2, A3, B1, B2, B3. Each column corresponds to a beta image which is the magnitude of the BOLD response under that condition. Following instructions in this document (ANOVAs and SPM by Henson and Penny, http://www.fil.ion.ucl.ac.uk/~wpenny/publications/rik_anova.pdf), I’ve created two contrast images per subject to bring to the second level analysis using these contrasts:

 

con1 = [-1.0  0.0 +1.0 +1.0  0.0 -1.0]

con2 = [-0.5 +1.0 -0.5 +0.5 -1.0 +0.5]

 

I have a few questions:

 

1) How do I perform the omnibus F-test (“group”x “AB”x”123”) at the second level?

2) can I include covariates (i.e. age and sex) in this second level omnibus F-test?

 

Thanks for any help!

Jon