# The Role of a Novel Population of Intrinsically Photosensitive Retinal Ganglion Cells in the Dorsal Retina

> **NIH NIH F30** · OREGON HEALTH & SCIENCE UNIVERSITY · 2020 · $50,520

## Abstract

Project Summary
Modern technological changes have lead to circadian misalignment in large portions of the population. This has resulted
in increased rates of metabolic, sleep, and mood disorders. The dysfunction is due to the vast range of biological clocks
that regulate many aspects of physiology. Entrainment of these clocks is achieved through the light and dark of the day-
night cycle sensed by a unique class of photoreceptors in the retina referred to as the intrinsically photosensitive retinal
ganglion cells (ipRGCs). Distinct from the rod and cone photoreceptors, which underlie the majority of visual perception,
ipRGCs form direct connections to non-visual areas of the brain and exercise bio-synchronous control over many
hormonal and neuronal aspects of body function. ipRGC-mediated light/dark entrainment is important for health
maintenance and interruptions can lead to endogenous clock dysregulation. This significant health burden demonstrates a
clear need for methods of circadian realignment and maintenance.
IpRGCs are responsible for encoding changes in ambient light across the entire retina but are far more complex than
originally anticipated. Though they only make up 2-5% of the RGC population in the eye, ipRGCs are diverse, consisting
of at least 6 distinct subpopulations that project to more than 30 discrete brain regions. While each of these classes express
melanopsin, they are thought to have distinct downstream signal transduction pathways. Therefore, each subpopulation is
extracting, encoding, and projecting different aspects of visual information in order to influence a separate collection of
light-driven behaviors. The specific functional roles of the majority of ipRGC subpopulations remain unclear.
To address this shortcoming we will investigate a previously undescribed subpopulation of ipRGCs present only in the
dorsal hemisphere of the retina. These ventral-coding ipRGCs express Cre under control of the glycine transporter and are
immunopositive for melanopsin and GABA. Their distribution and neurotransmitter type are characteristics that are thus
far unique among RGCs. Our goal is to understand their functional sensitivity, central connectivity, and signal
transduction pathways. I will do this using electrophysiology in isolated preparations of retina, Cre-dependent viral
tracing, and novel photochemical tools. We hypothesize that this dorsally located subpopulation of ipRGCs extract,
encode, and project information differently from the greater ipRGC population. This will be the first study describing this
novel neuronal population and will serve to generate techniques that can be applied to future investigations in the retina
and brain.
Artificial light contributes to interference of the biological clocks through the function of the ipRGCs. However, the
distribution and inhibitory neurotransmission of this novel subpopulation may suggest that location of light within the
visual field is important for regulation. The clinic...

## Key facts

- **NIH application ID:** 10069182
- **Project number:** 1F30EY031984-01
- **Recipient organization:** OREGON HEALTH & SCIENCE UNIVERSITY
- **Principal Investigator:** Michael Hayden Berry
- **Activity code:** F30 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $50,520
- **Award type:** 1
- **Project period:** 2020-07-01 → 2025-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10069182

## Citation

> US National Institutes of Health, RePORTER application 10069182, The Role of a Novel Population of Intrinsically Photosensitive Retinal Ganglion Cells in the Dorsal Retina (1F30EY031984-01). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10069182. Licensed CC0.

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