Dear freesurfer experts,

i am really a newbie in freesurfer.

I want to compare the thickness between different ages.

Is it correct to use gender as fixed factor, to look for its influence on thickness ?

If i find no effects of gender on thickness i can put the factor gender out of the model ?

Otherwise if there will be effects of gender on thickness it remains in the model. So that the effect of age on thickness

can be questioned like this:

Does the correlation between thickness and age, accounting for gender, differ from zero?

Best regards 

Daniel