Hi Steve, > 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.
Thanks that does all make sense and sorry that this is essentially an FSL question but... for completeness the thresholding is a result of voxels/nodes exceeding the 0.5 (activation/background) threshold level after the mixture modelling? Thanks. Bryan. > > Hope that makes sense, > Cheers, Steve. > > > > On 15 Sep 2014, at 01:41, Bryan Paton <[email protected] > <mailto:[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] <mailto:[email protected]> > http://www.fmrib.ox.ac.uk/~steve > --------------------------------------------------------------------------- > > Stop the cultural destruction of Tibet <http://smithinks.net> > > > > -- 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
