Thank you for your fast reply - your recommended use of mri_surf2surf and mri_surf2vol seems to have done the trick.

Best, Nela ________________________________________ From: Douglas N Greve [greve@nmr.mgh.harvard.edu] Sent: 06 January 2010 17:00 To: Nela Cicmil Cc: freesurfer@nmr.mgh.harvard.edu Subject: Re: [Freesurfer] w file overlay tkmedit - surface to volume?

You'll need to run mri_surf2vol, but first you'll need to convert from w to mgh format. Use mri_surf2surf to do this. Then something like:

mri_surf2vol --surfval lh.meg.mgh --hemi lh --fillribbon --identity subject --template $SUBJECTS_DIR/subject/mri/orig.mgz --o vol.lh.meg.mgh

doug

Nela Cicmil wrote:

Dear all,

I'm at a dead end and would be really grateful if anyone can help out: I have exported MEG source data into w file format and would like to overlay this data on the anatomical MRI volume images i.e. like the images seen in the tkmedit viewer. Is this type of display possible, and if so what is the best way to do it?

I've checked that the w files are easily visualized on the brain surfaces in the mne_analyze viewer and also in tksurfer, but when I try to overlay them onto tkmedit (either direct from terminal or through mne_analyze) I get this error:

Error: Loading functional overlay .../*-rh.w. Couldn't load MRI volume. Tkmedit couldn't read the functional volume you specified. This could be because the volume wasn't found or was unreadable, or because a valid header type couldn't be find, or a registration file couldn't be found or opened.

I assume that this error is because the w files are in surface format whilst tkmedit requires its overlays to be in volume format, so perhaps they need to be converted with mri_surf2vol - does anyone know what are the necessary arguments to acheive this with a w file? Alternatively, is there another way to show the w files, or other type of MEG source data format, on anatomical MRI volume images?

Thanks for your help, Nela

PS. I originally sent this query to the MNE mail-list, but perhaps this is really a freesurfer issue...

---

Nela Cicmil D.Phil Candidate, Neurophysiology Dept. Physiology, Anatomy & Genetics University of Oxford _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer

-- Douglas N. Greve, Ph.D. MGH-NMR Center greve@nmr.mgh.harvard.edu Phone Number: 617-724-2358 Fax: 617-726-7422

Bugs: surfer.nmr.mgh.harvard.edu/fswiki/BugReporting FileDrop: www.nmr.mgh.harvard.edu/facility/filedrop/index.html