Dear Freesurfer list,

I want to do a ROI analysis on longitudinally processed cortical thickness data in fsaverage space.

I followed the steps proposed for long. processing on http://surfer.nmr.mgh.harvard.edu/fswiki/RepeatedMeasuresAnova

(i.e sample each time point onto the average surface, concatenate the data into a single file and smooth it)

The design with three timepoints is the same as the design decribed on the webpage.

I have manually drawn the labels I want to use as ROIs in tksurfer on the fsaverage inflated surface, which worked.

But I dont know how to extract the thickness values (or the mean value/median etc)  in each manually defined ROI-label

from the concatenated and smoothed .mgh data file (I could not find a solution to this yet)

Can anybody help?

Thank you very much,

Andreas