# Excitatory and Inhibitory Activity Contributions to Hemodynamic Signals

> **NIH NIH R01** · UNIVERSITY OF PITTSBURGH AT PITTSBURGH · 2020 · $336,013

## Abstract

PROJECT SUMMARY/ABSTRACT
Most approaches to assess brain function and connectivity, including functional magnetic resonance imaging
(fMRI) and optical imaging of intrinsic signals (OIS), rely on activity-evoked changes in cerebral blood flow,
blood volume and/or blood oxygenation as indirect measures of neural activity. While these hemodynamic
methods are immensely valuable to map brain function and connectivity in humans and animals, fundamental
gaps remain in our understanding of neuro-vascular mechanisms due to its complexity and methodological
difficulties. This gap in knowledge greatly impedes our understanding of the driving neuronal processes
behind BOLD fMRI findings of brain function, dysfunction and development. The goal of this proposal is to
determine the role of excitatory and inhibitory neuronal activity, including glutamatergic and GABAergic
synaptic activity, in vascular regulation and their representation in hemodynamic signals. To activate specific
neuronal sub-populations in vivo, novel optogenetic mouse models expressing Channelrhodopsin-2 (ChR2) in
cortical excitatory or inhibitory neurons will be used. These optogenetic models will be combined with an
innovative approach to concurrently record neural and vascular signals under pharmacological conditions
designed to modulate glutamatergic and GABAergic synaptic transmission. Neural activity will be measured by
electrophysiology and two-photon calcium imaging. Vascular signals of blood flow will be obtained by laser
Doppler flowmetry, while OIS will be used to image changes in cerebral blood volume and blood oxygenation
(directly analogous to fMRI). These data will then be used to model and integrate excitatory and inhibitory
activity contributions to hemodynamic signals. This work will have a tremendous impact by advancing our
understanding of relevant neuro-vascular mechanisms as well as establish a more concrete framework that
can allow for a deeper understanding of the neuronal processes behind hemodynamic alterations in brain
development and dysfunction.

## Key facts

- **NIH application ID:** 9987715
- **Project number:** 5R01NS094404-05
- **Recipient organization:** UNIVERSITY OF PITTSBURGH AT PITTSBURGH
- **Principal Investigator:** ALBERTO L VAZQUEZ
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $336,013
- **Award type:** 5
- **Project period:** 2016-07-15 → 2022-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9987715

## Citation

> US National Institutes of Health, RePORTER application 9987715, Excitatory and Inhibitory Activity Contributions to Hemodynamic Signals (5R01NS094404-05). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9987715. Licensed CC0.

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