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MEG Data Injection

Salzburg

At the University of Salzburg, MEG data is converted by Andreas Huttegger using the ANC MEG conversion pipeline. The pipeline converts .fif files to BIDS format, extracts events from trigger channels using the dataset's config.yaml, and automatically opens a merge request in the dataset project.

Other sites

Researchers at other sites convert their MEG data independently (e.g. using MNE-BIDS or FieldTrip) and deposit it via the self-deposit workflow.

After conversion

  • MR is assigned to a user
  • User has followed the handbook
  • When everything is correct, they mark the MR as ready
  • Data steward is assigned as reviewer

Review checklist

Structure

  • Session directory is present (sub-<label>/ses-<label>/meg/) — mandatory in the ANC even for single-session studies
  • Filenames follow BIDS convention (sub-<label>[_ses-<label>]_task-<label>[_run-<index>]_meg.fif)
  • All required file pairs are present: data file + *_meg.json sidecar

Participant information

  • participants.tsv contains participant_id, sex, age, diagnosis for this subject
  • participants.json has a description for every column in participants.tsv

MEG sidecar (*_meg.json)

  • TaskName is present
  • SamplingFrequency is present
  • DewarPosition is present (Salzburg: upright)
  • DigitizedLandmarks and DigitizedHeadPoints are documented
  • Channel counts are consistent with the actual recording

Channel classification (*_channels.tsv)

  • Channel types are correctly labelled (MEG, MEGREF, ECG, EOG, STIM, MISC, etc.)
  • Stimulus/trigger channels are classified as STIM, not MEG

Events (*_events.tsv and *_events.json)

  • Events file is present for task recordings
  • onset and duration columns are present
  • trial_type values match the labels defined in the conversion config.yaml
  • Trigger codes 0 and 255 are absent (should be in ignore_triggers in config)
  • *_events.json contains a description for every column

Coordinate system (*_coordsystem.json)

  • Present
  • MEGCoordinateSystem and MEGCoordinateUnits are specified
  • Head shape / digitisation points are present if recorded