Dear Bruce,

Thanks for pointing me those information. That .tif file includes the mean and variance for the population sample that was used in Freesurfer. I would like to get similar measures for our own subjects. I think I could use the surface file (like surf/?h.sulc) in each subject folder to compute the mean and variance, right? Is this file already in spherical template space? Thanks again.

Best,
Liang

2012/9/14 Bruce Fischl <fischl@nmr.mgh.harvard.edu>
Hi Liang

yes, that information is encoded in the .tif file that is the target of the registration. You can use mrisp_paint to copy a frame out of
$FREESURFER_HOME/average/?h.average.curvature.filled.buckner40.tif

the tif file is 3 sets of triplets in different frames. The first is the mean of the measure, the second is the variance and the third is the degrees of freedom. The 3 triplets are for the curvature of the inflated surface, the sulc and mean curvature of the white surface.

cheers
Bruce


On Thu, 13 Sep 2012, liang wang wrote:

Dear FS folkers,
I am working on a functional probabilistic atlas. I find that some functional
regions (particular along a big sulcus) show quite high probability value over a
large sample, whereas the probability for some regions are quite lower. I think
this disparity could be accounted for by the anatomical variation on each surface
node that appears while surface-based registering individual surface to the average
template that was provided by Freesurfer. For instance, the anatomical variation
 could be pretty small within a big sulcus (like central sulcus). 

I assume that Freesurfer output a file which characterizes this type of anatomical
variation. Could someone point me which file it is and how to use it to create a
group-level measure in order to clear display somewhere has large variation.
Thanks.

Best,
Liang

--
Liang Wang, PhD
Neuroscience of Attention and Perception Laboratory
Princeton Neuroscience Institute
Princeton University
Princeton, NJ, 08540






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--
Liang Wang, PhD
Neuroscience of Attention and Perception Laboratory
Princeton Neuroscience Institute
Princeton University
Princeton, NJ, 08540