Hi Zhongming,
we always generate models of the hemispheres separately. We do generate BEM
surfaces, and can downsample. I'll cc Matti Hamalainen who can instruct you
on how this can be done.
Bruce
On Tue, 9 Aug 2005, Zhongming Liu wrote:
I am a new user of Freesurfer. My questions are related to the head modeling
and MEG/EEG source modeling.
1. Can freesurfer generate the 3-shell boundary element model (BEM): 3
triangulated interfaces of air-scalp, scalp-skull, skull-brain?
2. Is it possible to generate a closed and folded cortical surface
after the segmentation on MR images? Freesurfer seems to output two splitted
hemispheres of cortex. I am particularly concerning this, because I will use
the cortical surface to constrain the MEG/EEG source location and direction.
3. Is it possible to evenly (or nearly evenly) down-sample the vertices
of a fine cortical surface into around 6,000 points, onto which the
elementary dipole will be placed? Freesurfer generates the cortical surface
with a huge number of triangles, which makes it impossible for MEG-based
source imaging.
Looking forward to your reply.
Best regards,
Zhongming Liu
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