Hi,
I have 3 participant groups in my data set, all with 2 longitudinal time points approximately evenly spaced. I've run everyone through the longitudinal pipeline, and used the Monte Carlo simulation to find a cluster that differs in SPC between groups 1 and 2. Now I want to calculate the average SPC in that cluster for group 3, simply for qualitative reference.
I've extracted the cluster to a label using mri_surfcluster, mapped that label to each of the participants' surfaces using mri_label2label, and used mris_anatomical_stats to extract the average thickness in the ROI, and then I manually calculated SPC per subject. But, no matter whether I use participants' CROSS or LONG surfaces, I can't replicate the average SPC values in the "y.ocn.dat" file generated by the simulation.
My guess is that the difference arises because of the averaging -- I'm averaging over thickness, and then calculating SPC, whereas I'm guessing that the GLM calculates SPC per voxel, and then averages over the cluster.
Is there a way I can extract the average SPC for group 3 over this ROI?
Thanks, Rachel