Hi - if you only want to do single-session analysis there is no need to do the registration, but you will need to have it turned on to do multisession/multisubject analysis. If your data is already in standard space then you can do multisubject analysis, but not from the GUI - use the command-line (melodic --help) instead. Cheers. On 13 Jul 2010, at 15:49, Mohamed Bahri wrote: > Dear FSL expert, > > I would like to know if the registration step in melodic (Multi-session temporal concatenation) could be bypassed or not? I see that in Melodic (Single-session ICA) registration can be deactivated but what is the impact of this deactivation? Does the data preprocessed and registered with SPM could be analyzed with melodic (Multi-session temporal concatenation) without the Melodic Registration? > > Any suggestion or comment will be very appreciated. > > Thank you in advance, > > Mohamed > --------------------------------------------------------------------------- Stephen M. Smith, Professor of Biomedical Engineering Associate Director, Oxford University FMRIB Centre FMRIB, JR Hospital, Headington, Oxford OX3 9DU, UK +44 (0) 1865 222726 (fax 222717) [log in to unmask] http://www.fmrib.ox.ac.uk/~steve ---------------------------------------------------------------------------