# Photoreceptor signaling in primate retina

> **NIH NIH R01** · UNIVERSITY OF WISCONSIN-MADISON · 2022 · $355,554

## Abstract

Project Summary/Abstract
Human daylight vision is dominated by signaling in the fovea, a specialization unique to diurnal primates which
is responsible for half of the retinal output and hence input to the higher visual centers. Our high-definition central
vision is initiated in the cone photoreceptors which are packed in a dense and exquisite pixel array in the fovea.
This unique arrangement together with the specialized retinal circuitry is key for the highest spatial and chromatic
resolution attributed to our central vision. It is well known that the density and morphology of cone photoreceptors
differ remarkably between foveal and peripheral primate retina, but our knowledge about the physiological and
functional differences remain quite poor. Interestingly, our recent observations in primate retina have revealed
that the time course of cone signals in the fovea is two-fold slower than in the peripheral retina consistent with
the two-fold difference in the temporal sensitivity of our cone-mediated vision to high-frequency flicker. The broad
goal of our project is to determine the full breadth of heterogeneities in cone signaling, “retinotopy of function”,
across a range of visual inputs and functional properties. We will focus on three salient questions across three
aims: 1) What are the differences in key functional properties of signals originating in the primate cone
photoreceptors across the visual field? (2) Is cellular noise generated in cone phototransduction homogenous in
cones across the visual field and what limits does it pose for cone function and perception? (3) Do foveal cones
exhibit differences in function during natural vision compared to cones in rest of the primate retina? We will
answer these questions using electrophysiological recordings of responses from cones in primate retina and
models that describe cone function. The proposed work will provide a detailed insight into primate cone signaling
especially in the fovea. Death of cone photoreceptors is the primary cause for vision loss in retinal diseases that
attack the fovea such as macular degeneration. A therapy option that holds promise for such degenerative
diseases is stem cell derived photoreceptor replacement therapy. Our study will provide the much-needed
baseline information about foveal cone signaling to evaluate cone function in human stem cell derived retina for
designing effective stem cell-based therapies as a way to ultimately cure degenerative retinal diseases such as
macular degeneration and others.

## Key facts

- **NIH application ID:** 10337270
- **Project number:** 5R01EY031411-02
- **Recipient organization:** UNIVERSITY OF WISCONSIN-MADISON
- **Principal Investigator:** Raunak Sinha
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $355,554
- **Award type:** 5
- **Project period:** 2021-03-01 → 2026-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10337270

## Citation

> US National Institutes of Health, RePORTER application 10337270, Photoreceptor signaling in primate retina (5R01EY031411-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10337270. Licensed CC0.

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