Dear Freesurfers,

In Fischl et al. 1999 it is highlighted, that the topological structure of the original surface is preserved in the spherical space and due to the nature of a sphere, computations (distance, area) measures are easy to make.

My question now, concerns the comparability of distance measures between subjects in the group fsaverage sphere. My aim is to compare distances between peak voxels coordinates of two study populations, to figure out if a systematic difference exist between the peak voxel distances of the two study populations.

Can I compare the distances between peak voxels (vertices) between different subjects based on the fsaverage group sphere? So, is the comparability of distances between vertexes of individually spheres preserved in group fsaverage space?

Ps: I know that the distances in spherical space are not Euclidian but still geodesic

Best wishes and thanks in advance,

Christopher Milde, M.Sc. Biol.

Institute for Cognitive and Clinical Neuroscience

Central Institute of Mental Health Square J 5

68159 Mannheim, Germany

Christopher Milde, M.Sc. Biol.

Institute for Cognitive and Clinical Neuroscience

Central Institute of Mental Health Square J 5

68159 Mannheim, Germany

Phone:                  +49-621-1703-6313

E-mail:                  christopher.milde@zi-mannheim.de

Homepage:        http://www.zi-mannheim.de/

Office:                  Forschungs- und Verwaltungsgebäude, Room 230