# Characterization of neurovascular and neurometabolic coupling of the negative BOLD response in human

> **NIH NIH R01** · UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON · 2024 · $365,955

## Abstract

Project Summary
For task-based functional magnetic resonance imaging (fMRI), the positive blood-oxygen-level-dependent
(BOLD) response has been widely used and often assumed that it linearly reflects local neural activity.
However, a significant portion of brain regions responds with signal decreases upon activation, known as the
negative BOLD response (NBR). Although the negative BOLD response (NBR) and its origin have been
explored extensively, temporal characteristics and spatial structure of the NBR, and corresponding underlying
physiological dynamics are still poorly understood.
 We propose to investigate dynamics of the NBR evoked by a brief stimulus –the negative hemodynamic
response function (nHRF) and its underlying neurovascular and neurometabolic responses using our novel
experimental paradigms with high spatiotemporal resolution BOLD and arterial spin labelling (ASL) fMRI
modalities. High spatial and temporal resolution BOLD measurements will resolve temporal dynamics of the
nHRF as a functional of cortical depth and distance from adjacent positive BOLD responses along the cortical
surface. We also evaluated shift-invariant temporal linearity by measuring dynamics of the NBR for varying
stimulus durations. Fine spatiotemporal sampling ASL measurements in conjunction with a novel stimulus-
onset-time dithering scheme will provide accurate quantification of the cerebral blood flow associated with the
NBR within gray matter. We advance our novel computational model based on prompt arterial dynamics
observed in recent experimental studies, enabling estimation of realistic neurometabolic response associated
with the nHRF. The model will offer a better detailed interpretation of the underlying physiological components
associated with the nHRF.
 Our proposed research will provide a detailed understanding of neurovascular and neurometabolic
(de-)coupling associated with nHRF, expanding our knowledge of normal brain functions. Such details with
precision to understand the NBR and its physiology was not available in previous studies. Ultimately, success
of our proposed research will motivate use of the proposed fMRI approaches and modeling schemes for brain
pathologies that involve neurovascular and neurometabolic coupling.

## Key facts

- **NIH application ID:** 10745664
- **Project number:** 5R01NS121040-04
- **Recipient organization:** UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
- **Principal Investigator:** JungHwan Kim
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $365,955
- **Award type:** 5
- **Project period:** 2021-12-01 → 2026-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10745664

## Citation

> US National Institutes of Health, RePORTER application 10745664, Characterization of neurovascular and neurometabolic coupling of the negative BOLD response in human (5R01NS121040-04). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10745664. Licensed CC0.

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