Hi That's correct: the 3D NIFTI ICA maps are released "primarily for display purposes" - as you say, the cortical parts of these live on the cortical surface and are projected onto the 3D volumes - meaning indeed tha the volumes aren't "filled out" volumetrically. So when viewed on the surface, using the original CIFTI representation of these maps, they are contiguous and unthresholded.
The maps as seen in the 3D NIFTI volumes supplied are also unthresholded, but the thumbnail PNG snapshots of these are indeed thresholded by slices_summary, to make viewing clearer. Hope that makes sense, Cheers, Steve. On 15 Sep 2014, at 01:41, Bryan Paton <[email protected]> wrote: > Hi HCP people, > > In the group-ICA results (the ICA parcellations), there is a volumetric > MN152 3D version of the ICA maps released as a Nifti file > (melodic_IC_sum.nii). Each of the volumes/series in the Nifti file > corresponds to a separate ICA map. When looking at the different > volumes/series in the Nifti file (which are really just the 3D > projections of the surface or cortical ribbon) you can see that many > areas of the surface have non-zero values. The example PNG files showing > the ICA maps projected onto an axial slice are a very handy summary but > they show much more discrete ICA activity compared to the raw Nifti > images. Were the ICA maps thresholded in some fashion in order to > generate the summary PNG files? What threshold (if any) was applied? > > Thanks. > > Bryan. > > -- > Bryan Paton, PhD > > 770 Blackburn Rd > Building 220, Rm 141 > Monash University > Clayton, VIC, 3168 > Australia > > +613 990 29790 > > Research Fellow, School of Psychological Sciences > EEG Lab Manager > EEG & fMRI, TMS, TMS & EEG Liaison > Monash Biomedical Imaging > 770 Blackburn Rd, Clayton VIC > > http://sites.google.com/site/bryanpaton > _______________________________________________ > HCP-Users mailing list > [email protected] > http://lists.humanconnectome.org/mailman/listinfo/hcp-users --------------------------------------------------------------------------- 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) [email protected] http://www.fmrib.ox.ac.uk/~steve --------------------------------------------------------------------------- Stop the cultural destruction of Tibet _______________________________________________ HCP-Users mailing list [email protected] http://lists.humanconnectome.org/mailman/listinfo/hcp-users
