# In vivo three-photon microscopy of the cortical gray and white matter

> **NIH NIH R01** · UNIVERSITY OF COLORADO DENVER · 2024 · $514,646

## Abstract

PROJECT SUMMARY
Multiple Sclerosis (MS) is an inflammatory, demyelinating disease of the central nervous system that afflicts
nearly 1 million people in the United States alone. While MS is classically regarded as a white matter disease,
gray matter lesion load may exceed that of the white matter in patients with MS. The pathological features of
lesions differ between gray and white matter lesions. Interestingly, in lesions that span white and gray matter
regions, display pathological hallmarks of white matter-only lesions, suggesting that cellular environments
distinctly regulate oligodendrocyte loss and regeneration. Furthermore, attempts at remyelination are more
frequent in cortical versus white matter lesions regardless of patient age or disease duration. These findings
suggest that remyelination of gray matter regions may be specifically limited by decreased functional integration
of new oligodendrocytes compared to white matter regions. Understanding the regional differences in
oligodendrocyte loss and regeneration represents a clear unmet need in the MS research community. A major
limitation to understanding these regional differences is the inability to monitor the dynamics of oligodendrocytes
in white matter in the living brain. To overcome this obstacle, we will use new optical methodologies to determine
regional variability in oligodendrocyte cell behavior. We propose to use the superior penetration depth of three-
photon excitation fluorescence and longitudinal in vivo imaging to determine the effects of circuit-specific
neuronal activity and demyelinating injury on oligodendrocyte lineage cells in both superficial and deep areas of
the adult brain. The objectives of this proposal are: 1) evaluate how behaviorally-relevant neuronal activity
regulates gray and white matter oligodendrogenesis, 2) to elucidate whether behavioral interventions can equally
promote oligodendrocyte regeneration of the gray and white matter. The overall hypothesis of this proposal is
region-specific rates of oligodendrocyte precursor differentiation and integration govern the proportion of
myelination in healthy, adaptive, and regenerative contexts. This proposal represents a novel synthesis of
cutting-edge approaches in optical physics and oligodendrocyte biology, and breaks new ground in
understanding the mechanisms underlying the regulation of gray and white matter oligodendrocyte plasticity and
regeneration.

## Key facts

- **NIH application ID:** 10877098
- **Project number:** 5R01NS132859-02
- **Recipient organization:** UNIVERSITY OF COLORADO DENVER
- **Principal Investigator:** Ethan Garrett Hughes
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $514,646
- **Award type:** 5
- **Project period:** 2023-07-01 → 2028-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10877098

## Citation

> US National Institutes of Health, RePORTER application 10877098, In vivo three-photon microscopy of the cortical gray and white matter (5R01NS132859-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10877098. Licensed CC0.

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