thank you Donna I would think too! Sofia ----- Original Message ----- From: "Donna Dierker" <do...@brainvis.wustl.edu> To: "Caret, SureFit, and SuMS software users" <caret-users@brainvis.wustl.edu> Sent: Thursday, May 14, 2009 3:27 PM Subject: Re: [caret-users] white matter point on flattened surface
> Hi Sofia, > > Let's say you have an activation map (fMRI) in volumetric form for your > subject, for whom you also have a fiducial surface. Provided that the > fMRI has been volume-registered to the same anatomical used to generate > the fiducial surface. > > When you map that fMRI volume onto the surface, you always map to the > fiducial surface. (Note that the fiducial surface might be a white > matter, pial, or midthickness representation. If the surface was > generated using Caret, it's a midthickness surface. If it was generated > using, say, Freesurfer, then a midthickness surface is easily generated > by averaging the WM and pial surfaces.) > > Once the fMRI is mapped onto the fiducial surface, then you have a > node-scalar mapping that can be rendered/overlaid on any surface > configuration (flat, inflated, etc.). But one never maps to the > inflated/flat surfaces directly. > > It's worth mentioning that the Caret surface, being a midthickness > surface, won't necessarily intersect your white matter voxel. It > depends on the fMRI resolution and how the fiducial surface intersects > the fMRI volume there. There are various mapping algorithms that help > you get around this problem (gaussian being the most helpful, > probably). But if you have an actual white matter surface available, it > is possible to map to that, as well. If the voxel is deep in the white > matter, it will still not intersect the WM surface, but then it is of > questionable validity, I would think. > > Hope this helps, > > Donna > > On 05/14/2009 04:45 AM, s.cres...@campus.unimib.it wrote: >> dear Donna >> I have a we question concerning the overlapping metrical data on the flat >> map. >> If I have some voxel belonging to the white matter how does caret manage >> them with respect to the flat? >> >> thank you! >> sofia >> _______________________________________________ >> caret-users mailing list >> caret-users@brainvis.wustl.edu >> http://brainvis.wustl.edu/mailman/listinfo/caret-users >> > > _______________________________________________ > caret-users mailing list > caret-users@brainvis.wustl.edu > http://brainvis.wustl.edu/mailman/listinfo/caret-users ----------------------------------------------------------------- La tua mano puo' lasciare un segno importante. Dona il tuo 5 per mille al San Raffaele di Milano. E' SEMPLICE E NON COSTA NULLA. Basta indicare nell'apposito riquadro della dichiarazione dei redditi "Finanziamento della ricerca sanitaria" il codice fiscale della Fondazione Centro S. Raffaele del Monte Tabor: 03 06 42 80 153 e ricordarsi di firmare. Per saperne di piu': 5permi...@hsr.it o vai sul sito http://www.5xmille.org. _______________________________________________ caret-users mailing list caret-users@brainvis.wustl.edu http://brainvis.wustl.edu/mailman/listinfo/caret-users
