On 09/26/2012 12:36 AM, Darren Gitelman wrote:

Hi

I have 3 questions:

1. Does it affect the stats (or does it just affect the display) if I

use the fsaverage brain vs. the average of my subjects brains when running mris_preproc or when simulating the cluster statistics using mri_glmfit-sim?

It will affect it some because the tessellations will be different. I have not done too many experiments to measure it, but the one I did do showed very little difference when using a subject-specific atlas. Your mileage may vary. mri_glmfit-sim expects there to be tables for each atlas.

2. I downloaded the simulations for multiple comparisons correction

mult-comp_cor.tar.gz. (which I later realized were also in freesurfer/average/mult-comp-cor). How do I apply the simulations to my data (assuming I used fsaverage)? It doesn't really say on the group analysis page how to apply the *.cdf file (or I missed it).

Run mri_glmfit-sim with the --cache option. Run it with --help to get more info.

3. I see on the list that mention is made of a possible symmetric

template, and there is an fsaverage-sym directory in the file I downloaded. Is this template available?

Yes, see http://surfer.nmr.mgh.harvard.edu/fswiki/Xhemi

doug

Thanks, Darren

-- Darren Gitelman, MD Northwestern University 710 N. Lake Shore Dr. Abbott 11th Floor Chicago, IL 60611 Ph: (312) 908-8614 Fax: (312) 908-5073

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