Supported Data Formats¶

MEDUSA© Analyzer uses specific file structures to ensure compatibility and reproducibility across the Medusa ecosystem.

`.rec.bson` — Native MEDUSA© Format¶

This is the core MEDUSA© format used across the Analyzer, Kernel, and Platform.

Binary BSON-based container for biosignals and metadata.
Stores sampling rate, channel info, events, and annotations.
Fully compatible with the MEDUSA© Kernel backend.

BIDS (Brain Imaging Data Structure)¶

MEDUSA© Analyzer organizes processed data into a semi-BIDS directory structure to maintain consistency between sessions, subjects, and signal types.

All processed results are stored inside the folder selected by the user (referred to as {selected_folder}), following this hierarchy:

{selected_folder}/
└── derivatives/
    ├── preprocessed/
    ├── segmented/
    └── parameters/

Each of these folders may include subfolders for the subject (sub-XX), session (ses-YY) and anatomy (EEG, ECG, or other signals). For example:

{selected_folder}/derivatives/
├── preprocessed/sub-01/ses-01/EEG/
├── segmented/sub-01/ses-01/EEG/
└── parameters/sub-01/ses-01/EEG/

preprocessed/¶

Stores the .rec.bson files that contain the original recording object plus the preprocessed signal added to it. These files preserve all metadata and structure from the original recording, allowing the preprocessed data to be reloaded later without repeating the preprocessing steps. Example

sub-01_ses-01_band-delta.rec.bson

segmented/¶

Contains .mat files with only the segmented signal (epochs) resulting from event or condition-based segmentation.

Each file corresponds to a specific band, condition, and event, and includes the variable:

epochs → (n_epochs × n_channels × n_samples)

Example:

sub-01_ses-01_band-alpha_cond-eyesclosed_event-stim01.mat

parameters/¶

Stores one .mat file per parameter, band, condition, and event. These files contain the numerical results of each metric (e.g., PSD, mean, variance, entropy, connectivity).

For PSDs: variables psd and freqs are included.
For other metrics: the variable name matches the parameter label.

Example:

sub-01_param-psd_band-delta_cond-eyesClosed_event-stim01.mat

Converting external data¶

If your raw data is not in .rec.bson format, you can use the Converter integrated into the MEDUSA© Analyzer main window.

It allows you to:

Convert supported formats into .rec.bson
Export to BIDS-compatible structure automatically

You will find detailed instructions on the Converter later in this manual, in the Data Loader section of the EEG and ECG experiments.