Dear all,
Could anyone tell me how to interpret the curvature files that you can create with mris_curvature/mri_make_surfaces? The description on the website tells that the values represent something like:
Value in curvature file(*.H) = 1/R, with R being the radius of a sphere tangent to the white matter surface with units in mm.
It gets slightly more complicated however due to a normalisation step:
In recon-all, the normalisation flag is turned on by default. To what are the values normalised? Normalising R to the local cortical thickness or something similar? Or is normalised referring to statistical procedures like a z-transform or equivalent perhaps?
I am interested in the local geometry of the cortex and need to be able to interpret a value in millimetres but at the moment I don't know whether the default normalised values already are in 1/mm and without scaling or that I should re-run it without the normalise flag.
Cheers
Peter