# Intersectional genetic dissection of inner retinal circuits

> **NIH NIH F31** · NORTHWESTERN UNIVERSITY · 2020 · $41,182

## Abstract

Project Summary
Visual information in the mammalian retina is segregated into functionally and anatomically specialized channels
for parallel processing. The mouse retina contains approximately ~40 retinal ganglion cell (RGC) types. Each
type can be distinguished based on the spatiotemporal properties of their light responses and their distinctive
morphological features. The RGC types each perform complex neural computations to convey specific aspects
of the visual scene to retino-recipient areas of the brain. These complex computations arise from an interplay
between excitatory and inhibitory signals centered on the dendrites of individual RGC types. These computations
remain largely unresolved due to our lack of knowledge of the roles played by a diverse class inhibitory
interneurons, the amacrine cells (ACs). The purpose of this study is to characterize the response properties,
functional connections, and visual processing roles of a newly discovered amacrine cell, the CK2-AC1. This
project uses powerful intersectional strategies available in the mouse retina. Specifically, a CaMk2a-tTA driver
line is crossed with a tamoxifen inducible Slc32a1-iCreER driver line to exclusively label CK2-AC1 cells. The
response properties of CK2-AC1 are probed by genetically labeling with GCaMP6f, ChR2, and DREADDS. 2-
photon imaging is used to record dendritic Ca2+ signals to measure receptive field properties and determine
feature selectivity mechanisms. The results show that CK2-AC1 is a glycinergic OFF center cell that is both
orientation (OS) and object-motion sensitive (OMS). Experiments with ChR2 mapping revealed that CK2-AC1s
provide glycinergic inhibition to a type of ON-OFF orientation selective RGC named HD1-RGC along with several
other types of RGCs (HD2, F-minioff, and G4). Finally, the functional roles of CK2-AC1 in visual processing were
examined by using DREADDs to reversibly to reversibly silence activity. CK2-AC1 provided both orthogonal and
OMS suppression to HD1- and HD2-RGCs. These findings indicate that CK2-AC1 is a multi-tasking AC that
confers orientation selectivity and object motion sensitivity on different RGC types. This work will enhance our
understanding of specific retinal circuits and will provide a general template for a genetic dissection of inner
retinal circuits.

## Key facts

- **NIH application ID:** 10068590
- **Project number:** 1F31EY031985-01
- **Recipient organization:** NORTHWESTERN UNIVERSITY
- **Principal Investigator:** Andrew Oh Jo
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $41,182
- **Award type:** 1
- **Project period:** 2020-08-07 → 2023-08-06

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10068590

## Citation

> US National Institutes of Health, RePORTER application 10068590, Intersectional genetic dissection of inner retinal circuits (1F31EY031985-01). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10068590. Licensed CC0.

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