# Tandem Genetically Encoded Voltage and Calcium Indicator Mice for Optical Physiology of Excitable Cells

> **NIH NIH R21** · NORTHWESTERN UNIVERSITY · 2020 · $197,500

## Abstract

Electrophysiology has long been the gold standard for the characterization of electrical activity in excitable
cells. Whole-cell voltage and current clamp have proven to be invaluable techniques to our understanding of
ion channel biophysics and pharmacology. Mechanisms underlying intrinsic excitability of neurons and
cardiomyocytes, and dynamics of neuronal networks in health and disease have also be elucidated using
these electrophysiological approaches. However, with traditional electrophysiological techniques chemical
access to the cell is required and it is difficult to assay electrical activity with high spatio-temporal accuracy in
individual cells and larger populations of cells. The ability to measure activity from multiple cells simultaneously
is critical for diseases such as epilepsy, which involves localized networks or may generalized to involve the
entire brain. Additionally, traditional electrophysiological techniques require extensive training, and highly
specialized equipment. Recent advances in the use of genetically encoded voltage indicators (GEVI) and
genetically encoded calcium indicators (GECI) have allowed for the examination of excitable cells without the
use of electrodes. This growing assortment of genetically encoded tools are available in an array of colors with
varied sensitivity and kinetics. GEVIs such as ASAP1 and Ace2N-mNeon, and GECIs such as GCamp6F and
JRGeco1a produce large voltage-dependent or calcium-dependent fluorescence changes with millisecond
timescale kinetics that allow for highly accurate interrogation of electrical signals and calcium dynamics in
excitable cells. This project will develop a mouse model that intergrates genetically encoded voltage indicators
and calcium indicators into a Cre-reporter lines, to allow researchers to study electrical activity using optogentic
techniques across a wide range of diseases. Aim 1 will focus of the generation and benchmarking of plasmids
encoding dual GEVI and GECI genes, while Aim 2 will be to generate a mouse model of the best GEVI/GECI
combination identified in Aim 1, followed by validation and mapping of transgene expression and functional
testing in a well characterized mouse model of epilepsy.

## Key facts

- **NIH application ID:** 9853851
- **Project number:** 5R21OD025345-02
- **Recipient organization:** NORTHWESTERN UNIVERSITY
- **Principal Investigator:** CHRISTOPHER H THOMPSON
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $197,500
- **Award type:** 5
- **Project period:** 2019-02-01 → 2023-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9853851

## Citation

> US National Institutes of Health, RePORTER application 9853851, Tandem Genetically Encoded Voltage and Calcium Indicator Mice for Optical Physiology of Excitable Cells (5R21OD025345-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9853851. Licensed CC0.

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