Hello,

I'm new to Freesurfer and I was wondering whether anybody could tell me what steps I need to do in Freesurfer in order to conduct the following analysis?

I would like to know which sex differences in cortical thickness (subjects 12-18 years old) are present in the 12 year olds already. I've used qdec to calculate the main effect of sex in a) all participants (12-18) and b) in 12 year olds. Is there a way how to mask the 12-year olds' results with the whole group so that I can calculate which of the whole-group main effects are present before the age of 13?

Thanks a lot for any suggestions,

Klara