Part of ants registration suite
LaplacianThickness \,WM.nii GM.nii Out.nii {smoothparam=3} {priorthickval=5} {dT=0.01} use-sulcus-prior optional-laplacian-tolerance=0.001\/
a good value for use sulcus prior is 0.15 -- in a function :
1/(1.+exp(-0.1*(laplacian-img-value-sulcprob)/0.01))