Dear FreeSurfer experts,

I have MRI data of one group of subjects and would like to evaluate positive and negative correlations between cortical thickness and some biomarkers by excluding the potential effects of age and sex. I followed the FS tutorials (MailScanner has detected a possible fraud attempt from "secure-web.cisco.com" claiming to be https://surfer.nmr.mgh.harvard.edu/fswiki/FsTutorial/GroupAnalysisDemographics#DODSDesignMatrix) and have read previous posts on the FS´s mail archive but I would appreciate if you can check if my FSGD file and contrasts are right.

The FSGD file looks as follows:

GroupDescriptorFile 1
Title CTh_Bioma
Class Female
Class Male
Variables age biomarker

Input 4009 Female 60 222.0
Input 4014 Male     70 195.6

Input 4022 Male     68 230.2

Input 4027 Female 65 250.0 

Input 4039 Male     62 205.6

Input 4001 Male     63 270.2 

Input 4002 Male     78 245.5

Input 4004 Male     66 234.1

Input 4050 Female 62 210.0

And these would be my contrasts:

positive correlation between thickness and the biomarker: 0 0 0 1

negative correlation between thickness and the biomarker: 0 0 0 -1

Thank you very much in advance.

Best regards,

Steve.