Common data types

Preprocessed or cleaned data

Template:

<pipeline_name>/
    sub-<participant_label>/
        <datatype>/
            <source_keywords>[_space-<space>][_desc-<label>]_<suffix>.<ext>

Preprocessing in this context means transformations of data that do not change the number of dimensions of the input and are not explicitly covered by other data types in the specification. Examples:

  • Motion-corrected, temporally denoised, and transformed to MNI space BOLD series
  • Inhomogeneity corrected and skull stripped T1w files
  • Motion-corrected DWI files
  • Time-domain filtered EEG data
  • Spatially filtered EEG data

The space keyword is recomended to distinguish files with different underlying coordinate systems or registered to different reference maps. The desc (description) keyword is a general purpose field with freeform values, which SHOULD be used to distinguish between multiple different versions of processing for the same input data.

Note that even though space and desc are optional at least one of them MUST be defined to avoid name conflict with the raw file.

Examples:

pipeline1/
    sub-001/
        func/
            sub-001_task-rest_run-1_space-MNI305_bold.nii.gz
            sub-001_task-rest_run-1_space-MNI305_bold.json
pipeline1/
    sub-001/
        func/
            sub-001_task-rest_run-1_desc-MC_bold.nii.gz
            sub-001_task-rest_run-1_desc-MC_bold.json
pipeline1/
    sub-001/
        func/
            sub-001_task-rest_run-1_desc-fmriprep_bold.nii.gz
            sub-001_task-rest_run-1_desc-fmriprep_bold.json

All REQUIRED metadata fields coming from a derivative file’s source file(s) MUST be propagated to the JSON description of the derivative unless the processing makes them invalid (e.g., if a source 4D image is averaged to create a single static volume, a SamplingFrequency property would no longer be relevant).