Hi FreeSurfer community,

I have several questions regarding FreeSurfer's surface integral measurements. Perhaps there is a documentation page that answers these questions that someone can point me to that I haven't been able to find, or perhaps someone knows the answers to these questions off the top of their head.

I understand that the negative surface integral corresponds to gyral regions and the positive surface integral corresponds to sulcal regions, but how do these differ from the Natural Surface Integral?

Additionally:

Integrals add up a series of underlying measurements, what is the measurement they are adding here - ie. is it a sum of local curvature measurements?

What is the AreaNorm Natural Surface Integral?

What is the Mean Natural Surface Integral?

What is K, k1 and their differences from H, C, k2 etc.

Thanks so much for your help!

Jacob Levman, PhD

Boston Children's Hospital

Harvard Medical School