My understanding is that GI is also a global summary stat across the whole hem,
while lGI is *local* GI (vertex-wise). It measures how folded the cortex is at
that vertex. GI and lGI are based on area, while the folding index is based on
curvature. Truly different measures.
Gyrification Index (GI) = Pial surface area / Convex hull surface area
(Zilles et al., 1988)
Folding Index (FI) = |kmax|(|kmax|-|kmin|)
Van Essen and Drury 1997
On Sep 28, 2011, at 10:48 AM, Nick Schmansky wrote:
> have a look at this page:
>
> https://surfer.nmr.mgh.harvard.edu/fswiki/LGI
>
> folding index is typically a single number summarizing the amount of
> folding overall on a surface. freesurfer puts these measures in
> subjid/stats/?h.curv.stats.
>
> gyrification index is a new method created by maria schaer to create a
> surface-based measure of folding (points across a surface describing the
> local folding measures).
>
> n.
>
>
> On Wed, 2011-09-28 at 11:05 -0400, Alan Francis wrote:
>> Hi Bruce, Nick & Doug:
>>
>> How does Folding index differ from Gyrification index?
>>
>> thanks,
>>
>> Alan
>>
>> BIDMC
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