[Freesurfer] FSGD and Contrast to determine the effect of age on performance

Hi experts,

I am not sure if this has already been addressed in FS discussion.

If my fsgd file looks like following:

Class Male Class Female Variables Performance Age Input S1 Male 181 25 Input S2 Female 167 23 .... ....

I understand that the contrast matrix *[**0 0 1 -1 0 0]* represents whether there is a difference between the group (male/female)-performance slopes regressing out the effect of age. In other words, this matrix calculates whether two slopes i.e. one for males: thickness-performance slope and second for females: thickness-performance slope - are significantly different after regressing out the effect of age.

My questions are following:

(1) Is my above interpretation of contrast matrix *[**0 0 1 -1 0 0]* correct? (2) If my interpretation is correct, then I was wondering what will be the contrast matrix if *I want to check whether there is **significant effect of age on e.g. thickness-performance slopes after regressing out the effect of gender.* And what will be the corresponding fsgd file for that, any changes in that?

Thanks.