# BRAIN Initiative: Hierarchical Event Descriptors (HED): a system to characterize events in neurobehavioral data

> **NIH NIH RF1** · UNIVERSITY OF CALIFORNIA, SAN DIEGO · 2022 · $1,042,112

## Abstract

This two-year project will advance, integrate, document, and promote the use of the Hierarchical
Event Descriptor (HED) system to describe events in human neuroimaging and behavioral data
from research experiments and other sources in sufficient detail to support comparative analysis
of human brain dynamics across studies. Relating the recorded data dynamics to temporally-
specifiable changes in subject experience, action, and cognition is a major goal (and challenge) for
both neuroimaging and biomechanical imaging. Standardizing the annotation of recorded (or post
hoc identified) events across such data sets — recorded in diverse sensory environments involving
different participant tasks and/or task conditions — in a ‘machine-actionable’ way is essential for
systematic reproducible comparative analysis of archival data to enable discovery and modeling
of systems-level brain function as well as biomarkers of brain/behavioral function. The HED
system is to our knowledge the only ontological system addressing the problem of defining
experiential and behavioral events in experimental human neuroimaging and other studies
recording behavioral data. The release of third-generation HED represents a dramatic advance in
HED usability and annotation capabilities, including the capacity to simply encode the
experimental design and experimental structure as well to document experimental stimuli and
subject responses within the data in a machine-actionable form. This project will improve
supporting infrastructure, formalize HED governance and maintenance processes, support a
community of users developing library vocabularies for specialized subfields, and develop
additional tools for supporting analysis using HED on common analysis platforms. Substantial
effort will be expended in developing practical tutorials, case studies, and a body of open-source
HED annotated datasets. Further effort will be devoted to exploring and integrating HED into the
wider human neuroinformatics ecosystem including the BRAIN Initiative sponsored OpenNeuro
archive and the NEMAR data, tools, and compute resource.

## Key facts

- **NIH application ID:** 10480619
- **Project number:** 1RF1MH126700-01A1
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN DIEGO
- **Principal Investigator:** Arnaud Delorme
- **Activity code:** RF1 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $1,042,112
- **Award type:** 1
- **Project period:** 2022-08-05 → 2024-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10480619

## Citation

> US National Institutes of Health, RePORTER application 10480619, BRAIN Initiative: Hierarchical Event Descriptors (HED): a system to characterize events in neurobehavioral data (1RF1MH126700-01A1). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10480619. Licensed CC0.

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