Dear FS experts,

I finished running the GLM and I wonder what is the best way to further analyse my data in order to see if there is any relation between age (at seizure onset) and cortical thickness for my  patients versus control group.


1).  Why when I overlay the sig.mgh in tksurfer lh inflated, I get more clusters than the number of clusters obtained from mri_glmfit-sim?

2). What sig.mgh represents?

3) What's the real significance of a  cluster (how a cluster is formed)?

4). Why my thickness value in clusters (eg cluster no. 1 which coresponds to the posteriorcingulate) for subject no.1 is different that the thickness value obtained for the same region in the lh.aparc.stats while running recon-all?

5). After running the GLM should I use visualizing and plotting method to further analyse my data  and load FSGD file lh.gender_age.glmdir/y.fsgd?

6). Should  my ROI's be defined or be the same with my clusters?

7). What is the difference between GLM and Qdec? What method is the best to analyse the relation between age  and cortical thickness for my  patients versus control group?

8). Why when analysing with Qdec I get more clusters? Are this defining or representing the sig.mgh as in GLM?

9). When using Qdec were I can find as an output of results  the number of clusters and the cortical thickness value?


Thank you and have a great day!
Antonella