[MINC-users] cortical surface inflation

[Steve M. Robbins]

On Sun, Nov 27, 2005 at 07:37:05AM -0500, Marc Schoenwiesner wrote:

> in his BIC seminar talk some weeks ago Alan Evans mentioned the
> possible advantages of coregistering anatomical volumes on a sphere
> to decrease intersubject variability for fMRI analysis. Once the
> cortical surfaces are extracted how would one proceed to do this
> with the MINC tools? The cortical surfaces need to be inflated into
> spheres

As Jonathan Harlap suggested, inflation is the easy part.

> and a transformation to get from the volume- to spherical space 

This is the non-trivial part.  The extracted cortical surface is thin
so you'll need to do some kind of projection of the volume data onto
the surface.  I have done this with sulcal label data, but never with
anything like fMRI.  For labels I used simple heuristics like: label
the surface node closest to the voxel.

> and back in needed, I guess.

Going from the 2D sphere to the 3D volume isn't too hard
and is only for visualization, anyway.


Once you have each subject's data on the sphere, my "mni_surfreg" code
can be used to register them all to a standard space/template.  This
should reduce the intersubject anatomical variability and improve the
analysis.  This registration has been used in thickness analyses like
those that Jonathan mentioned.

-Steve