On 10/20/15 7:19 AM, Victor Montal Blancafort wrote:

FS experts,

I have seen several posts regarding volume-to-surface projections, but I am not 100% confident about which parameter should I use with mri_vol2surf that better fit my needs.

Currently, my data are several DTI-metric volumes per subject already normalized to MNI152 space (both 1mm and 2mm voxel sizes). My intention is to move cortex values of those volumes into the fsaverage surface space. I know that mri_vol2surf will work, but I have some doubts on how this work.

In general, this is a bad idea. You should keep everything in native space, then map to the native space of the subject, then to fsaverage. You'll lose a lot going from mni152 directly to fsaverage.

1. If no extra commands are used (i.e projfrac or projdist), what will

each value of the vertex mesh represent? A specific voxel value?

Yes

2. If my intention is to project the mean value across white and pial

surface, which exact command should I use?

Add --projfrac-avg 0 1 .1

3. There exists any specific command to move from MNI152 volume (FSL)

to fsaverage surface (avoiding bbregister)?

You can use spmregister or fslregister (though bbregister should work too)

4. Statistically, smoothing my data at the surface for further VBM

analyisis(i.e moving later the surface values to volumes), will introduce any bias?

I don't understand

Thank you in advance for your time and help! Cheers,

Victor Montal

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