BIDS organization for multimodal data acquired simultaneously


I’m relatively new to BIDS, and I’m trying to re-structure a collection of data for our lab. We collect simultaneous EEG/fMRI (participants enter the MR scanner wearing an MR-compatible EEG cap), and I was wondering if any BIDS experts have recommendations on how to build our dataset to indicate simultaneous recording took place. Are there any best practices for simultaneous multi-modal imaging acquisitions?

Sarah Guthrie

Hi Sarah.

There is nothing to my knowledge that is specific about simultaneous EEG/MRI in regards to BIDS. You can add acquisition label (which is optional) to indicate it was simultaneous, e.g., sub-XXX_task-XX_acq-EEGsimultaneous_bold.nii.gz (for fMRI).


Hi @sguthrie,

As @Steven notes, I’m not aware of a strict recommendation specific to simultaneous data. You might, though, be able to look at the simultaneous EEG-fMRI dataset noted in the BIDS-EEG paper for inspiration !


An old issue on the BIDs specification does relate to simulateneous recording but as said by @Steven there is currently nothing “specific” for this use case.

One thing that you can do is make sure that your scans.tsv mentions the same acq_time for data files that were acquired together.

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@Steven Thanks! I appreciate having a way for the files to be connected that doesn’t require a user to dig through the .tsv files.

@emdupre I’ve been looking at that dataset, thank you :blush:

@Remi-Gau I’ll make sure to include acq_time in the scans.tsv, thanks!

Depending on what platform and software you re familiar with several tools exist to help you – have a look at the starter kit and in particular file templates. Pybids and matlab-bids can also make making folders. Last but not least, if you used EEGLAB to process your EEG data you can automatically export a STUDY to bids and then add the fMRI ‘manually’.