As some additional explanation, the reason there are multiple files in the unprocessed data is that we did not acquire all the directions in a single scan (that would have been excessively long). Instead, they are split across several scans, which are separate files before preprocessing. The number of directions in each is deliberately slightly different in order to make it harder to mix up which one is which.
Tim On Wed, Jul 26, 2017 at 9:49 AM, Shruti Narasimham <naras...@tcd.ie> wrote: > Dear all, > > I am new to the HCP datasets and therefore a bit confused about the DWI > datasets uploaded. I would be very grateful if you could kindly clarify the > following: > > 1. 3T DWI data has scans with b-values 0,1000,2000,3000 while 7T has > with 0,1000,2000 ? > 2. Each subject has multi-shell data (different b-values within the > same dataset) ? > 3. The manual says that for the 3T data, 6 files exist for each > subject corresponding to 3 b-values and 2 phase encoding directions. The 3T > data has subject_name_dir95_AP, subject_name_dir96_AP, > subject_name_dir97_AP, subject_name_dir95_PA, and so on. I understand that > AP , PA corresponds to the phase encoding direction but what are the > different files for (dir 95, 96, 97) if according to point 2., each file > has different b-values? Why do 6 files exist in each subject's folder? If > these are for different gradient tables used, for CSD tractography can I > choose any one file with its corresponding bval and bvec file for analyses? > 4. Same goes for the 7T data, what do the dir71 and dir72 mean? How do > these files differ? I couldn't find any information for the 7T data in the > manual. > > > Apologies for the very basic questions. > > > > Looking for any help / clarification regarding these. > > > Thank you. > > > Regards, > Shruti > > _______________________________________________ > HCP-Users mailing list > HCP-Users@humanconnectome.org > http://lists.humanconnectome.org/mailman/listinfo/hcp-users > _______________________________________________ HCP-Users mailing list HCP-Users@humanconnectome.org http://lists.humanconnectome.org/mailman/listinfo/hcp-users
