Hi Suzanna, I am new to FSL as well, but previously, I was using another software for fiber-tracking and post-acquisition analysis. There were some proponents around me who suggested that along with the mean FA in a specific anatomical location, one should also document the mean number of fibers/voxel for that location and also the mean ADC (or perhaps a ratio of mean FA/ADC). Actually, now that I have mentioned it, I would be most interested in what you and the rest of our friends on this mailing list think about these parameters. Regards, Riaz Riaz Khan MD Research Assistant Dept of Psychiatry and Behavioral Neurosciences Wayne State University