Hi All,

In my study, subjects come twice, one time they receive drug and another they receive placebo. We are interested in the difference between drug and placebo, so we did a paired t test. Now, we have some behavioral measures we want to put in the model to see how they modulate the brain reaction. If, for example, someone with higher BDI will have stronger reaction in some parts of the brain for drug-placebo contrast.
I have set up the model as shown in the attachment, with paired t test + one more EV.
Because the same subject comes twice but each person only has one behavioral result, so the second half of the covariate is just the original covariate number * -1. (Is this done correctly? or should I put zeros?)
Now, what should I do for the contrast to see the covariates' effect? Is c[100001] correct?

  1   1   0   0   0     2
  1   0   1   0   0     4
  1   0   0   1   0    -5
  1   0   0   0   1    -1
 -1   1   0   0   0    -2
 -1   0   1   0   0    -4
 -1   0   0   1   0     5
 -1   0   0   0   1     1