1. in freesurfer v5, there are now multiple fsaverage subjects with varying number of vertices. fsaverage6 has about 40,000 vertices per hemi, so you can just include the flag:

--target fsaverage6

after the -qcache flag, and it will use that as the target instead of fsaverage (producing files like 'rh.thickness.fsaverage6.mgh', which will have 40K thickness samples).

2a. i've just posted a new mris_convert which will combine surfaces. you can download it at:

ftp://surfer.nmr.mgh.harvard.edu/pub/dist/freesurfer/misc/linux-centos4_x86_64

usage is:

mris_convert --combinesurfs lh.white rh.white ./both.white.gii

view with:

freeview --surface both.white.gii

2b. see mris_convert --help for examples of converting parcellation data (ie. .annot files) to gifti label files.

n.

On Fri, 2010-09-10 at 15:19 +0800, Dai Dai wrote:

Hi, all

I am a new user of freesurfer and now I have two questions.

1. For my work, the number of vertex in surface data is too much to

process. How can I downsample the surface mesh as well as the curvation file (e.g. thickness)? The vertex number of fsaverage template is ~160,000, normally more than that of every subject. Can I construct an average surface of less vertexes or downsample the fsaverage surface to that of ~20000 vertexes and then transform all the subjects using these templates with less vertexes (using recon-all -qcache)?

2. How can I convert the freesurfer surface format to gifti, with two

hemisphere surfaces in one gifti file. And how can I write the parcellation of surface to another gifti file which is corresponding to the gifti of surface data?

Many thanks.

2010-09-10

---

Neural Imaging Computation and Analysis Group, Key Lab of Complex Systems and Intelligent Science, Institute of Automation, Chinese Academy of Sciences(CASIA) Beijing, China _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer