What are the advantages of FreeSurfer over VBM?
• FS uses geometry to do inter-subject registration, which experience has shown results in a much better matching of homologous cortical regions than volumetric techniques. FS allows you to look at the two components of volume separately (thickness and surface area). It has been found that these two do not necessarily track one another, and in the worst case where one is increasing and the other decreasing the volume change can be 0. The target that FS uses for registration (the white matter surface geometry) is completely invariant to gm atrophy, so gm changes won’t result in a different registration.
