1 Getting Started

You are here because you would like to use EEG data from the Healthy Brain and Child Development (HBCD) Study.

1.1 Overview

This document describes the structure and contents of EEG data folders for the HBCD Study. The data are structured and formatted according to standardized Brain Imaging Data Structure (BIDS) conventions and were processed using the Maryland Analysis of Developmental EEG (MADE) pipeline (Debnath et al., 2020). For additional information about the data processing pipeline used, visit https://pubmed.ncbi.nlm.nih.gov/32293719/.

Each subject’s data folder contains all available data for each EEG acquisition session. When these folders are downloaded and uncompressed, all data, processing output, and relevant information will be accessible and organised according to BIDS format.

Each subject’s folder is named with PSCID_DCCID_VisitNumber_Task. The PSCID and DCCID are different unique identifiers, with the PSCID containing information about whether the folder contains pilot (denoted with QI) or main study data (denoted with CH) as well as a proceeding acronym representing the study site at which the data were acquired. This manual will replace subject and study visit identifiers with asterisks when referring to specific file names.

Each subject folder contains data re-saved across multiple stages of processing, as described below. The data are saved at four times: raw (unprocessed), filtered, with ICA decomposition, and post-processing. We chose to provide the data at multiple stages of the processing pipeline to facilitate the adjustment of any procedures without having to restart pre-processing with raw data.

The following folders and individual files are contained within each subject’s main data folder:

  • ./filtered_data
  • ./merged_data
  • ./ica_data
  • ./processed_data
  • ./sub-******
  • ./dataset_description.json
  • ./participants.json
  • ./participants.tsv
  • ./README
  • ./sub-******_ses-***_acq-eeg_MADE_preprocessing_report
  • ./subject_session_task_MADE_specification.json

Section 2 describes the contents of each folder and file in detail.

1.2 File Types

The following file types will be found within the subject’s main folder or any given subfolder.

  • SET- contains metadata and parameters for the EEG dataset, such as channel locations, sampling rate, and event information.

  • FDT- field data table (FDT) files contain EEG data.

  • JSON- stores metadata and configuration settings in a format that is easy for users to read and edit

  • TSV- plain text file that stores metadata and other relevant information

  • JPEG- images and plots as output from the MADE processing pipeline

  • MAT - MATLAB data files contain processing output

  • EDAT3- contains task-specific event information from E-PRIME, the stimulus presentation software

  • TXT- text files contain descriptive information