Dear FreeSurfer community, I am one of the developers of NeuroVault.org - an open repository for vizualizing, analyzing, and sharing of statistical and parcellation maps of the human brain. So far NeuroVault was limited only to volumetric data in the MNI space since this is the most common way of reporting MRI results. Now I would like to start working on adding support for surface data beginning with outputs of FreeSurfer. Since I'm not a FreeSurfer expert I would like to ask the community a few questions:
1. In NeuroVault users are asked to upload their statistical maps in form of files. I'm planning to target outputs of mri_glmfit: preferably Z.mgh but also sig.mgh. Is this the most sensible thing to do?
2. I want to be able to tell if a given map is in fsaverage space. Is there any place in the .mgh header that specifies which space the map is in?
3. fsaverage has different subsampling flavours - how often are they used? Is support for them an important feature?
4. Results come in two files - one per each hemisphere. Is there any way (from the headers) to check if two files provided by a user match?
5. As with the volumetric data I want to provide a 3D interactive viewer. I had some initial success with Brain Browser. Are you aware of any other javascript based viewers that work well with FreeSurfer data?
6. Which surface should be the default view: inflated, pial, or white?
7. Finally NeuroVault gives users ability to compare maps and even search through the whole repository to find statistical maps with similar patterns. This is currently implemented for volumetric data, but could be extended to surface data. The problem arises when one wants to compare MNI volumetric data with fsaverage surface data. So far I have been using mri_vol2surf with target subject being fsaverage (with a supplied affine correction matrix), but this solution is far from optimal since fsaverage folding patterns are quite different from MNI. I was thinking that maybe a more accurate way of dealing with this would be to reconstruct MNI152 cortical surface model, do surface registration of it to fsaverage, and use that to sample statistical maps in MNI space. What do you think?
Thank you for any help feedback you can provide!
Best, Chris Gorgolewski