by Stefanie Rudrich* and Jose Raul Naranjo**
*Team Leader of Marketing (Brain Products)
**Product Manager BrainVision Analyzer (Brain Products)
Scientific experiments often result in complicated data that can be arranged in many ways. Even two researchers working in the same lab sometimes arrange their data differently. The lack of standards on how to organize and share data, leads to misunderstandings and the wasting of time on rearranging data or rewriting scripts. To counter this problem and create commonly accepted standards for organizing and sharing neuroimaging data, the BIDS (Brain Imaging Data Structure) standard was established.
In the beginning, the goal of BIDS was mainly to create standards for the description, handling and sharing of MRI (Magnetic Resonance Imaging) datasets. In the meantime, efforts were expanded and standards for storing and sharing multidimensional MEG (Magnetoencephalography) data were also defined.
Most recently, the BIDS standard has also included two new extensions for Electroencephalography (EEG-BIDS) and intracranial Electroencephalography (iEEG-BIDS). These are used for standardizing, organizing and sharing freely distributed EEG and iEEG datasets within the neuroscience research community.
The extension of BIDS to EEG and iEEG data closely follows the general BIDS specification. Each subject’s data corresponds to a directory of raw data containing subdirectories for each session and data modality. The figure below provides an approximate representation of the transition from custom EEG file naming and organization to the EEG-BIDS standard. More details are reported in the EEG-BIDS and iEEG-BIDS publications.
Due to the robustness and widespread use of Brain Products’ BrainVision Core Data Format 1.0 (BVCD), BIDS has adopted it as one of the recommended official EEG/iEEG data formats.
Brain Products GmbH has granted permission for BIDS to freely publish and share the format specification across the open-source neuroscience research community. Widely-used, free, and open software packages have already adopted the BIDS standards (e.g. EEGLAB, FieldTrip, MNE-Python, BrainStorm, SPM).
All rights on the BrainVision Core Data Format are reserved by Brain Products GmbH (e.g. changes on the data format can only be made by Brain Products GmbH).
To give you a brief overview, an EEG recording consists of three separate files:
- Header file (*.vhdr): This is a text file containing recording parameters and further meta-information. It has the same base name as the raw EEG data file.
- Marker file (*.vmrk): This is a text file describing the events that have been collected during the EEG data recording. It has the same base name as the raw EEG data file.
- Raw EEG data file (*.eeg): This is a binary file containing the EEG data as well as additional signals recorded along with the EEG.
For further information refer to the official documentation of our BVCD format.
We are happy to be part of this movement and would like to thank the BIDS community for their efforts. Stay tuned for more BIDS-related developments we have in the pipeline.
To read more about how Brain Products supports open science, check out the Brain Products Open Access Grant.