On 11/19/2012 12:28 PM, angela.favaro@unipd.it wrote:
Dear list, I am quite new in the use of freesurfer and I have two doubts.
- I am studying the visual areas of the brain, but I do not know how to
perform a vertex analysis within a ROI. I already know how to obtain thickness data on a ROI (either drawn by hand or labeled), but I would like to restrict the area of a vertex-analysis to my ROI (visual brain areas)
When you run mri_glmfit, you can pass it a label (--label) or mask (--mask) in which you specify only the areas you want to analyze. You will need to re-run the simulation for the correction for multiple comparisons since your search space has changed.
- When performing a vertex-analysis, is it correct to include TIV (total
intracranial volume) as a nuisance variable?
It depends on what you are analyzing. I think for thickness, people are not doing a correction. For volume, they are. For surface, a correction is often done, but not with the raw TIV (maybe taking the 2/3 root to give it surface dimensions). doug
Thank you for any help
Angela
Angela Favaro, MD, PhD Psychiatric Clinic Department of Neurosciences via Giustiniani 3 35128 Padova Italy
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