> ## Documentation Index
> Fetch the complete documentation index at: https://docs.autocleaneeg.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Exploring the BIDS Folder

> Understand the structure and files created in the `bids/` folder, including metadata, subject folders, and processed outputs.

# The `bids/` Folder

Each pipeline run outputs results in **BIDS (Brain Imaging Data Structure)** format, a widely adopted standard for EEG and neuroimaging data. This ensures your cleaned data are interoperable with other tools (e.g., EEGLAB-BIDS, MNE-BIDS, BIDS Validator).

The `bids/` subfolder contains:

* **Raw-like cleaned EEG data** in BIDS layout
* **Standard metadata files** describing participants, dataset structure, and channels
* Events and a derivatives folder for reproducibility

<Tip>
  Because BIDS enforces strict formatting rules, the **subject identifier (`sub-XXXX`)** inside the `bids/` folder will not necessarily match the original filename.\
  To see how subjects are linked to original recordings, check the **`participants.tsv`** file, which maps subject IDs to participant metadata.
</Tip>

```
└── RestingStateTutorial/ 
    └── bids/ 
        ├── dataset_description.json 
        ├── sub-451559/ 
        ├── participants.tsv 
        ├── participants.json 
        ├── README 
        └── derivatives/ 
```

## File and Folder Overview

| File / Folder                  | Purpose                                                                                 |
| ------------------------------ | --------------------------------------------------------------------------------------- |
| **`dataset_description.json`** | Required by BIDS. Records dataset name, pipeline version, and references.               |
| **`participants.tsv`**         | Table listing subjects and basic attributes (age, sex, etc.).                           |
| **`participants.json`**        | Sidecar describing the meaning, format, and units of each column in `participants.tsv`. |
| **`README`**                   | Free-text description of the dataset, study, or preprocessing notes.                    |
| **`sub-<ID>/`**                | Per-subject folder (e.g., `sub-451559`) containing the actual EEG data and metadata.    |
| **`derivatives/`**             | Numbered stage folders (e.g., 01\_import … 16\_comp) used for stepwise inspection.      |
| —                              | — (Final user‑facing exports live at the task root under `exports/`).                   |

## What to Expect

* **Raw-like cleaned EEG** lives under each subject folder (`sub-<ID>`).
* **Metadata** (`dataset_description.json`, `participants.tsv/json`, `README`) ensures the dataset is machine-readable and human-readable.
* **Processed derivatives** contain stage outputs for debugging/inspection.
* **Final deliverables** (EEG‑only sets) live under the task‑root `exports/` folder.