yes. On Wed, 15 Feb 2006, Roberto Toro wrote:

Hi,

I found the reference to D. Van Essen's paper:

Van Essen, D and Drury, H (1997) "Structural and functional analyses of human cerebral cortex using a surface-based atlas" J Neurosci 17(18):7079-7102

and the folding index is defined (from that paper) as "the integral of the product of the maximum principal curvature and the difference between maximum and minimum curvature, divided by 4*pi", ie,

FI= (1/4pi) \int \int |kmax|(|kmax|-|kmin|) dA

is this what freesurfer is using?

thanks,

roberto

On 8 Feb 2006, at 16:39, Bruce Fischl wrote:

...

the Gaussian and mean curvature are differential geometric measures and you can find them in any standard textbook (e.g. do Carmo). The folding indices come from one of David Van Essen's papers - sorry, I don't have the reference offhand, but it shouldn't be too hard to find.

Bruce

On Wed, 8 Feb 2006, Goradia, Dhruman D wrote:

...

Hi,

The output of function "mris_anatomical_stats" contains the following measurements: integrated rectified mean curvature, integrated rectified Gaussian curvature, folding index and intrinsic curvature index. Can someone please give me a brief explanation of what these measurements are or suggest some reading material.

-Dhruman

Dhruman D. Goradia (M.S.)

Research Specialist.

Western Psychiatric Institute and Clinic.

3811 O'Hara St. Suite 431

Pittsburgh, PA 15213

Phone: 412-586-9017

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1. Not offhand.

for the others run:

set sdir=$SUBJECTS_DIR/$s/surf mris_curvature -max $sdir/lh.white

this will write a file named lh.white.max (or use the pial if you want). Similarly:

mris_curvature -min will write the min curvature

and

mris_curvature -w will write the Gaussian (to lh.white.K) and mean (to lh.white.H) curvatures.

cheers, Bruce

On Thu, 16 Feb 2006, Roberto Toro wrote:

three more quick questions: (1). do you know of a paper using the folding index successfully? (2). is it possible to access k_max and k_min for every vertex? (3). is it possible to access the mean curvature and the gaussian curvature for every vertex? (... to obtain (2)...)

thanks, roberto

On 15 Feb 2006, at 17:28, Bruce Fischl wrote:

...

yes. On Wed, 15 Feb 2006, Roberto Toro wrote:

...

Hi,

I found the reference to D. Van Essen's paper:

Van Essen, D and Drury, H (1997) "Structural and functional analyses of human cerebral cortex using a surface-based atlas" J Neurosci 17(18):7079-7102

and the folding index is defined (from that paper) as "the integral of the product of the maximum principal curvature and the difference between maximum and minimum curvature, divided by 4*pi", ie,

FI= (1/4pi) \int \int |kmax|(|kmax|-|kmin|) dA

is this what freesurfer is using?

thanks,

roberto

On 8 Feb 2006, at 16:39, Bruce Fischl wrote:

...

the Gaussian and mean curvature are differential geometric measures and you can find them in any standard textbook (e.g. do Carmo). The folding indices come from one of David Van Essen's papers - sorry, I don't have the reference offhand, but it shouldn't be too hard to find. Bruce On Wed, 8 Feb 2006, Goradia, Dhruman D wrote:

...

Hi, The output of function "mris_anatomical_stats" contains the following measurements: integrated rectified mean curvature, integrated rectified Gaussian curvature, folding index and intrinsic curvature index. Can someone please give me a brief explanation of what these measurements are or suggest some reading material. -Dhruman Dhruman D. Goradia (M.S.) Research Specialist. Western Psychiatric Institute and Clinic. 3811 O'Hara St. Suite 431 Pittsburgh, PA 15213 Phone: 412-586-9017

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