Dear experts, I have 18 ROIs and I performed probtrackx to find the probability of connection from each seed to all targets. Now I am interested to know the actual number of fibers between each ROIs. If I understand correctly, probtrackx does not give you any information about the count of fibers. Should I use deterministic tractography to obtain this information? If so which tool and tractography algorithm do you suggest? Appreciate your help. Saeideh Bakhshi, http://www.cc.gatech.edu/~sbakhshi/ <http://www.cc.gatech.edu/%7Esbakhshi/> PhD Student, Georgia Institute of Technology College of Computing 266 Ferst Drive, Suite 3337 Atlanta, Georgia 30332