# Non-canonical GABAergic Pathways in the Visual System

> **NIH NIH R01** · NORTHWESTERN UNIVERSITY · 2020 · $486,934

## Abstract

PROJECT SUMMARY
 Light is a profoundly important regulator of physiology and behavior across a wide range of organisms.
Light information is relayed from the retina to the brain via glutamate released from retinal ganglion cells
(RGCs) at more than 40 brain regions, with some RGCs also co-releasing peptide transmitters. Despite the
prevailing dogma that all RGCs release glutamate, there have been hints that some RGCs may be GABAergic.
However, the identity and function of these potentially GABAergic RGCs is completely unknown. Our recent
findings indicate that a subset of the melanopsin-expressing, intrinsically photosensitive (ip)RGCs are
GABAergic. This proposal will test the overarching hypothesis that GABA release from the melanopsin-
expressing, intrinsically photosensitive (ip)RGCs influences non-image forming behaviors. The aims of this
proposal will define the types and targets of GABAergic RGCs and their role in visual behavior using a
combination of mouse genetics, channelrhodopsin-based circuit tracing, anatomy, patch clamp
electrophysiology, and behavior. In addition to mapping the identity and function of GABAergic RGCs, these
studies will open up new areas of research into the role of inhibitory circuits in light-driven behavior and
physiology.

## Key facts

- **NIH application ID:** 9972467
- **Project number:** 1R01EY030565-01A1
- **Recipient organization:** NORTHWESTERN UNIVERSITY
- **Principal Investigator:** Tiffany M. Schmidt
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $486,934
- **Award type:** 1
- **Project period:** 2020-07-01 → 2025-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9972467

## Citation

> US National Institutes of Health, RePORTER application 9972467, Non-canonical GABAergic Pathways in the Visual System (1R01EY030565-01A1). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9972467. Licensed CC0.

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