Freesurfers-
I am looking to investigate the whether cortical thickness varies in regards to a continues variable, while controlling for other continues variables. I am having a little trouble wrapping my head around this as i am unsure how to compare thickness in regards to a continues variable, how the contrast would look, ect. Looking at this example FSGD ( http://surfer.nmr.mgh.harvard.edu/fswiki/Fsgdf2G1V)
GroupDescriptorFile 1 Title OSGM Class Group1 Class Group2 Variables Age Input subject1 Group1 30 Input subject2 Group2 40
I am thinking i may need to randomly define two groups, and then use a contrast similar to 0 0 0.5 0.5 (contrast 4 on the same page). Which asks:
Null Hypothesis: does mean of group age slope differ from 0? Is there an average affect of age regressing out the effect of group?
Am i correct in thinking that if i use this contrast i would be able to determine whether there is a difference in cortical thickness based on any continuous variable (like age, IQ)?
Michael