2 groups and 2 within-subject factors

[Aimee Flores]

Dear all,

I have an fMRI design comparing the BOLD in movement and rest. I have a design with 2 groups, and 2 within subjects factors (A and B), with 2 levels each ( A1, A2, B1 and B2).

First, I calculated the the contrast of movement - rest in the first level

Now I would like to use SWE to check if

1) there is no difference between groups

2)  there is an interaction between the 2 within subject factors

I have unfortunately not found any example with this design and was wondering if you could advice me on this. Or point me to some documentation.

Thank you for the help.

Best wishes, 

Aimee Flores

[Aimee Flores]

In particular, I was confused by other comments in this forum in which they added the intercept, as well as the factors to be tested as covariates.

I have therefore the followign questions: 

1)  if I use the GUI, in which area should I add the intercept?

 2)  Should I add a matrix of the size of the scans added and with the factor levels in the covariates section? or where could I specify the design matrix. 

Thank you so much in advance for the help.

Best wishes, 

Aimee Flores