Interesting. What would you need it for? Do you want to weight the correlation between voxels by the their axon distance? Maybe we can recruit a student who wants to do a project and has programming skills to do this?
---------------------------------------------------- Dr. Leon Y Deouell, MD, PhD Department of Psychology The Hebrew University of Jerusalem Jerusalem 91905 Israel Tel: +972-2-5881739 Fax: +972-2-5825659 http://pissaro.soc.huji.ac.il/~leon/Lab _____ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Alon Keren Sent: Wednesday, July 11, 2007 5:57 PM To: caret-users@brainvis.wustl.edu Subject: [caret-users] ROI definition by connection distance Hi. I have been using CARET a lot lately, and found it very powerful and useful for a variety of applications. There is a feature that I am interested in, and I think is not available at the moment. I am interested in a sophisticated measure of distance between nodes: The "real" distance, or functional or connection distance between two nodes is neither euclidean nor geodesic. Two nodes on opposite walls of a sulcus are further away in the connectivity sense then two nodes on opposite walls of a gyrus, with white matter bridging the gap. In the first case a geodesic measure is suitable, whereas in the second an euclidean measure is more adequate. I imagine it is much more complicated to implement, but a measure of distance that goes around CSF but cuts through WM would be very useful and more accurate for functional purposes. For instance I would like to estimate the relationship between this functional distance and co-activation of nodes. A question on the same topic: Is there an automatic way to produce a matrix of node to node geodesic distances (of size #ofNodes^2)? Thanks, Alon.
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