# Functional Connectivity Network in default mode regions provides the underlying infrastructure for task-based functional co-de/activation networks

> **NIH NIH R01** · WEILL MEDICAL COLL OF CORNELL UNIV · 2022 · $786,178

## Abstract

Summary
Recent developments demonstrate that the brain carries out its functions through a number of large-scale
functional sub-systems, or networks. One of the most studied brain networks is the default mode network
(DMN); however, the internal structure of the DMN, and how it carries out its functions, still remains elusive.
The topography of the DMN has been mapped using four different imaging techniques: through reductions in
the blood flow of DMN regions during task engagement using 15O-PET; as the hypermetabolic regions at rest
using FDG-PET; as the task-based deactivation using BOLD-fMRI; and through functional connectivity in
resting-state fMRI. The task-based blood-flow reductions observed in 15O-PET studies, and task-based
deactivations observed using BOLD-fMRI, seem to be reflective of the same neurophysiological processes,
since BOLD signal is highly confounded by blood flow. It has also been postulated that resting-state functional
connectivity and hypermetabolism in DMN regions reflect the same neurophysiological process; thus
concluding that the resting-state functional connectivity is the measurement of the brain’s baseline, intrinsic, or
resting-state activities. However, recent evidence has put such possibility under question by indicating that
resting-state functional connectivity networks are active during anesthesia, sleep, and even task-performance.
Such findings raise a critical, but as of yet unanswered, question: what is the role of such overlapping networks
in DMN regions? We hypothesize that functional connectivity in the DMN regions is representative of a lower
level process, which provides the underlying infrastructure for the higher-level network that carries out the
actual function.
 Both functional connectivity and task-based deactivation in the DMN regions have been reported to be
disrupted with normal aging, the pre-clinical stage of Alzheimer’s disease, mild cognitive impairment and
Alzheimer’s disease. However, since the assumption in the field is that the DMN’s functional connectivity and
task-based deactivation are representative of the same underlying neurophysiological process, there has been
no study, to our knowledge, investigating the cascade of the events in which functional connectivity or negative
BOLD response get disrupted. Disentangling the cascade of events in the AD is crucial for understanding the
disease initiation, progress, and treatment. Our preliminary evidence in this project demonstrates that imposing
alteration in the task-based deactivation network does not have any effect on the functional connectivity of the
same regions. The current proposal will use asymptomatic stage of Alzheimer’s disease to test whether
disruption in the underlying functional connectivity results in any change to the task-based deactivations in the
DMN, which is an evidence for hierarchical structure.

## Key facts

- **NIH application ID:** 10406379
- **Project number:** 5R01AG057962-05
- **Recipient organization:** WEILL MEDICAL COLL OF CORNELL UNIV
- **Principal Investigator:** Qolamreza Ray Razlighi
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $786,178
- **Award type:** 5
- **Project period:** 2020-07-01 → 2024-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10406379

## Citation

> US National Institutes of Health, RePORTER application 10406379, Functional Connectivity Network in default mode regions provides the underlying infrastructure for task-based functional co-de/activation networks (5R01AG057962-05). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10406379. Licensed CC0.

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