Spatial smoothing in the volume?

Discussions
1

Hi Francois,
I would like to do some spatial smoothing within the MRI volume after source estimation in the volume. The standard process does not work - it says it only works on the surface. Is there an other way to do this?
Thank you,
Esther

2

Hi Esther,

I’m sorry, I don’t have any function for doing this. The process for smoothing the surface-based results is using the SurfStat toolbox, which is only handling tesselations.
We also agreed collectively that the results obtained with unconstrained source models would be smooth enough not to require any additional smoothing.

I’m not sure you’d find easily functions to smooth scattered data points with a Gaussian kernel. The easiest solution might be to reinterpolate on a fixed grid (the MRI voxel space for instance), smooth using Matlab’s convn, then interpolate the results back to the scattered grid. Or process the reinterpolated+smoothed volume directly (as it is done for the SPM export: https://neuroimage.usc.edu/brainstorm/ExportSpm8)

Cheers
Francois