Dear all,
I want to include both a covariate of interest and a nuisance covariate in my
design matrix (2nd level analysis; one sample t-test; SPM5). My question
regards the contrast specification.
The design matrix has 3 columns: 1st column: con images of subjects; 2nd
column: covariate of interest; 3rd column: nuisance covariate.
What is correct (t-contrasts): 0 1 0 or 1 1 0 (to see activations)?
Is it possible to look at both contrasts, since 1 1 0 gives me far more
significant results than 0 1 0? (I fear that 0 1 0 is "correct".)
How will I calculate deactivations (0 -1 0 or -1 1 0)?
I would be very grateful and happy for an answer!
Thank you very much indeed.
(I try to analyze data of one group of subjects and a block design with two
alternating conditions; thus, the con images are contrasts of condition A
versus condition B).
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