The FSGD looks right (you have a 2x4 design, so 8 classes, plus 2 covariates).

[1 1 -1 0 0 -1 0 0 0 0 0 0 0 0 0 0] tests for a difference between NoFocus and RhFocus (No-RH)
[0 0 1 -1 0 1 -1 0 0 0 0 0 0 0 0 0] tests for a difference between RhFocus and LhFocus (RH-RH)

probably you can figure out the rest from the pattern

On 5/2/14 4:40 PM, Kenza Drissi wrote:

Dear Marie,

I want to run a group analysis on a set of subjects, correcting for gender
(Male/Female), diagnois regarding epilepsy (no focus/focus in rh/focus in
lh/focus in both h), age and IQ. Should my FSGD file look somewhat like this
below:

GroupDescriptorFile 2

Class NoFocus_Male
Class NoFocus_Female
Class RhFocus_Male
Class LhFocus_Male
Class BhFocus_Male
Class RhFocus_Female
Class LhFocus_Female
Class BhFocus_Female

Variables age IQ

If so, considering that I want to investigate the effect of epilepsy on cortical
gyrification, what should my contrast matrix look like?
The hypothesis is that the gyrification index is diminished for epileptic
patients, probably more when there is bilateral focus.

I know that we need as many number as regressors, so I expect there to be 10
numbers, is it so?

Thank you so very much for clarifying this point,
Kenza
_______________________________________________
Freesurfer mailing list
Freesurfer@nmr.mgh.harvard.edu
https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer