Dear Andrew
      Thank you for your quick reply. I have learned a lot under your guidance.
      I kind of understand the contrast, but just want to double check with you the individual means of the design matrix.
If there are 8 pateints in each group, My design matrix is as foliows. My contrast for the interaction effect is [0 1 0 0 0 0 0 0] or [0 -1 0 0 0 0 0 0]; My exchange blocks is [1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2]. Are they correct?
I also want to enter covariates such as head movement,age,sex and body mass index. How to modify my design matrix, and Where can I add it in the software interface of NBS ? Thank you very much.

Sincerely,
zhangyue

    Sham-pre: -1 1 1 0 0 0 0 0 ----subject1
    Sham-pre: -1 1 0 1 0 0 0 0 ----subject2
    Sham-pre: -1 1 0 0 1 0 0 0 ----subject3
    Sham-pre: -1 1 0 0 0 1 0 0 ----subject4
    Sham-pre: -1 1 0 0 0 0 1 0 ----subject5
    Sham-pre: -1 1 0 0 0 0 0 1 ----subject6
    Sham-pre: -1 1 0 0 0 0 0 0 1 ----subject7
    Sham-pre: -1 1 0 0 0 0 0 0 0 1 ----subject8
    Active-pre: -1 -1 0 0 0 0 0 0 0 0 1  ----subject9
    Active-pre: -1 -1 0 0 0 0 0 0 0 0 0 1 ----subject10
    Active-pre: -1 -1 0 0 0 0 0 0 0 0 0 0 1  ---- subject11
    Active-pre: -1 -1 0 0 0 0 0 0 0 0 0 0 0 1---- subject12
    Active-pre: -1 -1 0 0 0 0 0 0 0 0 0 0 0 0 1 ----subject13
    Active-pre: -1 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 ----subject14
    Active-pre: -1 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 ---- subject15
    Active-pre: -1 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 ---- subject16
    Sham-post: 1 -1 1 0 0 0 0 0 ----subject1
    Sham-post: 1 -1 0 1 0 0 0 0 ----subject2
    Sham-post: 1 -1 0 0 1 0 0 0 ----subject3
    Sham-post: 1 -1 0 0 0 1 0 0 ----subject4
    Sham-post: 1 -1 0 0 0 0 1 0 ----subject5
    Sham-post: 1 -1 0 0 0 0 0 1 ----subject6
    Sham-post: 1 -1 0 0 0 0 0 0 1 ----subject7
    Sham-post: 1 -1 0 0 0 0 0 0 0 1 ----subject8
    Active-post: 1 1 0 0 0 0 0 0 0 0 1 ----subject9
    Active-post: 1 1 0 0 0 0 0 0 0 0 0 1 ----subject10
    Active-post: 1 1 0 0 0 0 0 0 0 0 0 0 1 ---- subject11
    Active-post: 1 1 0 0 0 0 0 0 0 0 0 0 0 1---- subject12
    Active-post: 1 1 0 0 0 0 0 0 0 0 0 0 0 0 1 ----subject13
    Active-post: 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 ----subject14
    Active-post: 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 ---- subject15
    Active-post: 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 ---- subject16