I am new to the Gifty format, and I have downloaded the BrainVisa files and visualised the surface correctly. For the application I have in mind, I would need a bit more than the surface mesh. In particular, I need to simulate, for testing purposes, a connectomic matrix that goes with the mesh. Namely, if the mesh has N vertices, I would like an N-by-N, possibly sparse matrix, indicating an approximation of the structural connection between each nodes.

Is there any dataset available with that type of matrix? I am happy to download other surfaces, of course. Note that for the application I have in mind this need not be a very accurate matrix. I just want to run a model in which vertices are connected to each other, and I thought there must be some standard dataset available for this.

Thanks

Daniele

The problem with such vertex-by-vertex connectivity matrices is the size: meshes from BrainVisa (as you say this is what you have used) are often 60-70000 vertices per hemisphere, and you need both for a complete connectivity matrix, thux a NxN matrix would be about 30-40 GB in size. So we are generally using sections of matrices (restricted to a region, connecting to the full brain) and coarser meshes (Freesurfer for instance can produce meshes at several resolutions like 32000 vertices or less, or it's also possible to decimate the meshes in brainvisa, but it will still big if you need to keep a certain precision), and/or sparse matrices using a home file format (because there are no standards for this - to my knowledge CIFTI has not been widely adopted (yet?) and I'm not sure it can handle sparse data). Anyway we don't have a dataset ready, sorry.

Denis