# Multimodal study of infra-slow propagating brain activity

> **NIH NIH RF1** · PENNSYLVANIA STATE UNIVERSITY, THE · 2020 · $1,151,024

## Abstract

PROJECT SUMMARY
The highly-organized intrinsic brain activity, as measured by resting-state functional magnetic resonance imaging
(rsfMRI), is being widely used to measure functional brain connectivity in both healthy subjects and patient
groups, despite the underlying neural mechanisms remain largely unclear. Converging evidence has suggested
that infra-slow propagating activity may play an important role in generating rsfMRI connectivity and dynamics,
and it thus could be the key to understanding the neural basis of rsfMRI connectivity and the functional role of
intrinsic brain activity. However, the study of the infra-slow propagating brain activity remains limited and mostly
used rsfMRI, which faces a serious issue for inferring propagating activity due to region-specific hemodynamic
delays. The lack of a clear understanding of the infra-slow propagating activity has greatly hinder the
understanding of functional roles of intrinsic brain activity and also hamper the interpretation and use of rsfMRI-
based connectivity/dynamics measures in various brain diseases. To bridge this critical gap, the major goal of
this application is to combine multimodal data from large-scale, publicly available datasets to fully characterize
the infra-slow propagating brain activity and elucidate its neurophysiological basis, structural correlates, and
functional relevance. The research objective will be achieved through three specific aims. Aim 1 is to
characterize and compare the infra-slow propagating activity in rsfMRI and electrophysiological signals collected
from both human and monkeys. It is hypothesized that the infra-slow propagating activity is present in both
human rsfMRI and monkey electrophysiology, and mostly along a hierarchical axis linking the lower- and higher-
order cortical regions. Aim 2 is to elucidate the relationship between the infra-slow propagating activity and
various structural/morphometric brain properties. The hypothesis is that the cross-hierarchy propagating activity
is closely linked, across subjects, to the cross-hierarchy contrast of certain structural/morphometric properties,
and they both account significantly for inter-subject behavioral variability. In Aim 3, the functional relevance of
the infra-slow propagating activity will be determined through its modulation across various brain conditions. It is
hypothesized that the cross-hierarchy propagating activity is significantly modulated across wake and sleep, in
PD patients, dependent on the spectral gradient of the brain, and show similar dynamics as ripple-trigger brain
activity. The proposed research is innovative because it will combine multimodal data from 5 independent
datasets to have a comprehensive understanding of the infra-slow propagating activity with focusing on its cross-
hierarchy features and using a novel methodology designed for detecting and quantifying single propagating
instances. The impact of this research is significant because it is expected to sig...

## Key facts

- **NIH application ID:** 10012212
- **Project number:** 1RF1MH123247-01
- **Recipient organization:** PENNSYLVANIA STATE UNIVERSITY, THE
- **Principal Investigator:** Xiao Liu
- **Activity code:** RF1 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $1,151,024
- **Award type:** 1
- **Project period:** 2020-07-06 → 2025-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10012212

## Citation

> US National Institutes of Health, RePORTER application 10012212, Multimodal study of infra-slow propagating brain activity (1RF1MH123247-01). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10012212. Licensed CC0.

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