[Mne_analysis] mne_read_surfaces

[Li Su]

Dear MNE group,

Sorry to bother people during the Christmas and New Year break. I have a question about how to load the surface files in order to analyse triangulation information.

I use the mne_read_surfaces function in Matlab to load the surface information of the whole brain. As stated in the manual, it returns a structure with a field .tris, which indicates "vertex numbers of triangles in counter clockwise order as seen from outside". To valid if the vertices in each raw of this field are indeed forming a tiny triangle, I visualise them using mne_analyse with the same surface loaded.

Then, I performed a series of test by typing some random raws of the field of .tris in the bottom part of the GUI where it says "vertex # :". A tiny red cross appears on the surface marking out where the vertex is. I marked out all three vertices from the same raw of .tris. However, I was very surprised to see that these red crosses are way apart from each other and not forming a triangular shape!

I am not sure if I misunderstand what this triangulation information really means, or there is anything else I did wrong.

Many thanks for your answer and helps!

Li Su

--
Li Su, PhD

MRC Cognition and Brain Sciences Unit
15 Chaucer Road
Cambridge CB2 7EF
United Kingdom

Phone +44 1223 273632 (direct line)

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mail.nmr.mgh.harvard.edu/pipermail/mne_analysis/attachments/20101230/dd9a68b4/attachment.html