Hello all
I have made deep changes in 9 regions of a left hemisfere of a subject surface after maped it onto the fsaverage subject sphere. The changes were made to have areas close to 15 mm^2. I computed the areas by add the areas of the faces inside the regions (computed using the vertexes spherical coordinates). The freesurfer sphere mapping is based in minimal metric distortion, so, why I got the following differences?:
Region Computed areas (mm^2) Computed areas (mm^2) uing mri_surfcluster as explained before with the fsaverage sphere 1 27.56 15.0522 2 21.78 15.0946 3 21.41 15.1087 4 20.77 15.1501 5 19.28 15.1797 6 16.60 15.1918 7 15.99 15.2781 8 14.31 15.3373 9 13.89 15.0541
In both cases the same surface vertexes were found to be inside the regions
Another thing:
Should I use the sig.mgh file resulted from the mri_glm estimation as the input to the mri_surfcluster function in MonteCarlo simulations? (plus the .csd file of course).
In advance thank you a lot Jorge
______________________________________________ LLama Gratis a cualquier PC del Mundo. Llamadas a fijos y móviles desde 1 céntimo por minuto. http://es.voice.yahoo.com
How did you get the 15 mm^2 regions? And how did you know that they are 15mm^2? There are some complications with using the raw vertex areas on fsaverage. The total surface area of the average will be wrong (inevitable with the way that fsaverage is computed). However, there is a correction, and our tools take this into account.
doug
jorge luis wrote:
Hello all
I have made deep changes in 9 regions of a left hemisfere of a subject surface after maped it onto the fsaverage subject sphere. The changes were made to have areas close to 15 mm^2. I computed the areas by add the areas of the faces inside the regions (computed using the vertexes spherical coordinates). The freesurfer sphere mapping is based in minimal metric distortion, so, why I got the following differences?:
Region Computed areas (mm^2) Computed areas (mm^2) uing mri_surfcluster as explained before with the fsaverage sphere 1 27.56 15.0522 2 21.78 15.0946 3 21.41 15.1087 4 20.77 15.1501 5 19.28 15.1797 6 16.60 15.1918 7 15.99 15.2781 8 14.31 15.3373 9 13.89 15.0541
In both cases the same surface vertexes were found to be inside the regions
Another thing:
Should I use the sig.mgh file resulted from the mri_glm estimation as the input to the mri_surfcluster function in MonteCarlo simulations? (plus the .csd file of course).
In advance thank you a lot Jorge
______________________________________________ LLama Gratis a cualquier PC del Mundo. Llamadas a fijos y móviles desde 1 céntimo por minuto. http://es.voice.yahoo.com _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
I computed the region areas by adding the areas of the triangular faces inside these regions using the spherical coordinates of the vertexs and the Heron formula for the triangle area.
Another thing:
Should I use the sig.mgh file resulted from the mri_glm estimation as the input to the mri_surfcluster function in MonteCarlo simulations? (plus the .csd file of course).
In advance thank you a lot Jorge
--- Doug Greve greve@nmr.mgh.harvard.edu escribió:
How did you get the 15 mm^2 regions? And how did you know that they are 15mm^2? There are some complications with using the raw vertex areas on fsaverage. The total surface area of the average will be wrong (inevitable with the way that fsaverage is computed). However, there is a correction, and our tools take this into account.
doug
jorge luis wrote:
Hello all
I have made deep changes in 9 regions of a left hemisfere of a subject surface after maped it onto the fsaverage subject sphere. The changes were made
to
have areas close to 15 mm^2. I computed the areas
by
add the areas of the faces inside the regions (computed using the vertexes spherical
coordinates).
The freesurfer sphere mapping is based in minimal metric distortion, so, why I got the following differences?:
Region Computed areas (mm^2) Computed areas
(mm^2)
uing mri_surfcluster as explained beforewith the fsaverage sphere 1 27.56 15.0522 2 21.78 15.0946 3 21.41 15.1087 4 20.77 15.1501 5 19.28 15.1797 6 16.60 15.1918 7 15.99 15.2781 8 14.31 15.3373 9 13.89 15.0541
In both cases the same surface vertexes were found
to
be inside the regions
Another thing:
Should I use the sig.mgh file resulted from the mri_glm estimation as the input to the
mri_surfcluster
function in MonteCarlo simulations? (plus the .csd file of course).
In advance thank you a lot Jorge
______________________________________________ LLama Gratis a cualquier PC del Mundo. Llamadas a fijos y móviles desde 1 céntimo por
minuto.
http://es.voice.yahoo.com _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu
https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
-- Douglas N. Greve, Ph.D. MGH-NMR Center greve@nmr.mgh.harvard.edu Phone Number: 617-724-2358 Fax: 617-726-7422
In order to help us help you, please follow the steps in: surfer.nmr.mgh.harvard.edu/fswiki/BugReporting
______________________________________________ LLama Gratis a cualquier PC del Mundo. Llamadas a fijos y móviles desde 1 céntimo por minuto. http://es.voice.yahoo.com
jorge luis wrote:
I computed the region areas by adding the areas of the triangular faces inside these regions using the spherical coordinates of the vertexs and the Heron formula for the triangle area.
On fsaverage? If so, then you will need to take into account the effect that I described. Also, those ROIs are pretty small, so there could be some local distortions.
Another thing:
Should I use the sig.mgh file resulted from the mri_glm estimation as the input to the mri_surfcluster function in MonteCarlo simulations? (plus the .csd file of course).
Yes, use the sig.mgh file
doug
In advance thank you a lot Jorge
--- Doug Greve greve@nmr.mgh.harvard.edu escribió:
How did you get the 15 mm^2 regions? And how did you know that they are 15mm^2? There are some complications with using the raw vertex areas on fsaverage. The total surface area of the average will be wrong (inevitable with the way that fsaverage is computed). However, there is a correction, and our tools take this into account.
doug
jorge luis wrote:
Hello all
I have made deep changes in 9 regions of a left hemisfere of a subject surface after maped it onto the fsaverage subject sphere. The changes were made
to
have areas close to 15 mm^2. I computed the areas
by
add the areas of the faces inside the regions (computed using the vertexes spherical
coordinates).
The freesurfer sphere mapping is based in minimal metric distortion, so, why I got the following differences?:
Region Computed areas (mm^2) Computed areas
(mm^2)
uing mri_surfcluster as explained beforewith the fsaverage sphere 1 27.56 15.0522 2 21.78 15.0946 3 21.41 15.1087 4 20.77 15.1501 5 19.28 15.1797 6 16.60 15.1918 7 15.99 15.2781 8 14.31 15.3373 9 13.89 15.0541
In both cases the same surface vertexes were found
to
be inside the regions
Another thing:
Should I use the sig.mgh file resulted from the mri_glm estimation as the input to the
mri_surfcluster
function in MonteCarlo simulations? (plus the .csd file of course).
In advance thank you a lot Jorge
______________________________________________ LLama Gratis a cualquier PC del Mundo. Llamadas a fijos y móviles desde 1 céntimo por
minuto.
http://es.voice.yahoo.com _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu
https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
-- Douglas N. Greve, Ph.D. MGH-NMR Center greve@nmr.mgh.harvard.edu Phone Number: 617-724-2358 Fax: 617-726-7422
In order to help us help you, please follow the steps in: surfer.nmr.mgh.harvard.edu/fswiki/BugReporting
______________________________________________ LLama Gratis a cualquier PC del Mundo. Llamadas a fijos y móviles desde 1 céntimo por minuto. http://es.voice.yahoo.com
freesurfer@nmr.mgh.harvard.edu
-
Doug Greve -
jorge luis