You are right except for the last step. The surfaces are not
retessellated to a common space. When it comes time for group analysis,
overlays (eg, thickness) are sampled into the group space (not the
surfaces themselves)
On 9/24/2020 9:40 PM, Pam Garcia wrote:
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Thanks for your response Bruce, just to clarify
If I understood, the wm surface is created using a surface deformation
procedure that adaptively determined the MR intensity of the
boundaries in question at each point in the cortex. Next a sphere from
the wm inflated surface is computed, warps the sphere into a 2-D file
containing the curvature and convexity patterns of the subject, and
then registers the 2D file with a reference (parameterization
template). This is executed to ensure that the curvature and convexity
patterns are aligned with a generic reference template. The mean and
the variance of curvature and convexity from the smooth and inflated
surface are used in order to do more robust the register. Finally, the
pial surface is created by expanding the white matter surface so that
it closely follows the gray-CSF intensity gradient, keeping the same
topology (number of vertex, edges, faces) and the vertex index is
preserved. Finally, the vertex of the wm and pial surface are mapped
in a common space and is here where we obtained vertex correspondence
across the subjects.
Thanks
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