Hi FreeSurfer community:
I wanted to ask for general thoughts on spatial smoothing of data.
In particular, some searching of the archives reveals that a bit of smoothing can help the quality of the data, as well as the inter-subject registration of significance volumes.
FreeSurfer can perform both volume-based smoothing and surface-based smoothing. Theoretical concerns and some testing seem to indicate that smoothing along the surface yields more robust results and more consistent results on the data in practice-is this correct?
Secondly, I have read some of the general thoughts about smoothing (more localized region, less smoothing; more subjects, less smoothing). Does anybody have some more practical insight into appropriate smoothing kernels for anatomical data (e.g. thickness), and functional data (typically BOLD, typically recorded at 3 x 3 x 4mm)? I'm interested in subject pool sizes between 10 and 50.
Thanks very much in advance for all of the help and thoughts-
Joakim