To software developers and investigators interested in the technical specifics of CIFTI files for neuroimaging data:

The CIFTI-1 data file format introduced in 2011 is used extensively in the datasets publicly released by the Human Connectome Project (HCP, http://www.humanconnectome.org/). In the course of generating these data and the tools to analyze them, the HCP software development team encountered several limitations with the CIFTI-1 file format. The CIFTI-2 format proposed herein addresses these limitations and provides additional features that are useful for handling fMRI and MEG data. Details of the proposed CIFTI-2 format are in the "CIFTI-2_ConnectivityFileFormats_Draft_8jan2014.pdf" document posted here on NITRC.

This posting solicits comments and suggestions from anyone interested in the CIFTI data format and its technical specifications. Open discussions of this type benefited the development of CIFTI-1 as well as the analogous GIFTI and NIFTI data formats that have proven invaluable for the neuroimaging field.
Because the proposed changes for CIFTI-2 are not backwards-compatible with CIFTI-1, it is preferable to increment the version number. The specific changes are described in "CIFTI-2_ConnectivityFileFormats_Appendices_Draft_8jan2014" " (in a separate NITRC posting because only one attachment is allowed).

We look forward to feedback regarding the CIFTI-2 proposal. We aim to finalize these changes in the coming month, by early February, 2014.

If you are interested in learning more about CIFTI, several recent publications in a special issue of Neuroimage illustrate the utility of the CIFTI format for HCP data (Glasser et al.; http://www.ncbi.nlm.nih.gov/pubmed/23668... Smith et al.; http://www.ncbi.nlm.nih.gov/pubmed/23702...); and Barch et al., http://www.ncbi.nlm.nih.gov/pubmed/23684...)

Sincerely,
The HCP Software Development Team