Hi Freesurfers, I am reposting this as my last email bounced.
I have conducted a DODS analysis in qdec with group (controls vs patients) set as my fixed factor and age as a nuisance variable to determine if my groups differ in cortical thickness. Controls were added first in the .levels file followed by patients. When I view the results in the display window for "do controls differ from patients in cortical thickness" I see a significant cluster for the caudal anterior cingulate, denoted by a red-orange blob and a positive t-value. I'm wondering if this simply means that controls had greater cortical thickness compared to patients after controlling for age? The reason I ask is that I'm a little confused since when I created an ROI for this cluster using tksurfer and then extracted the means and sd, I see that the patients actually have larger means than the controls, the opposite of my interpretation of the results presented by the qdec display. Furthermore, if I extract the means and sds for the entire caudal anterior cingulate using the aparc file, I get means that are larger in controls, compared to patients, which seems consistent with qdec. Any ideas? Thanks for all the help.