[Freesurfer] GLM question

Hi FS folks,

I have a basic GLM question. I went through the tutorials online but I was not sure and wanted to check with someone.

I am trying to compare the cortical thickness between a group of patients (n = 166) and controls (n = 76).

For patients mean age is 49.8 +/- 9.1 and there are 55 Male; 111 Female For controls mean age is 40.5 +/- 11.4 and there are 26 Male; 50 Female

If include gender as a fixed factor does the output of the GLM answer the following: 1. "Is the cortical thickness different between the patients and controls accounting for gender"

2. As I understand the GLM setup one can control for gender and other discrete factors but not for continuous co-variates such as age ? That is one can find the association between thickness and age and see if it is different for the two groups. However if the age distributions for the two groups are different one cannot control for it with GLM. is this interpretation correct ?

If so, how would one control for age in such an analysis ?

Any help is much appreciated.

Thanks Mehul

2. For the correction of multiple comparisons, when should one use FDR as compared to monte-carlo simulations ?

Thanks Mehul