# Opto- and chemogenetic neural activity recording with diverse reporters

> **NIH NIH R01** · STATE UNIVERSITY NEW YORK STONY BROOK · 2021 · $343,246

## Abstract

PROJECT SUMMARY/ABSTRACT
The brain's control of our thoughts, feelings, and behaviors stems from neural circuits, which perform logical
operations based on the temporal patterns of neural activity and the connectivity of the neurons as the circuit
traverses the brain. Recent studies have produced many strategies for visualizing and controlling a circuit's
neural activity. In some cases, specialized microscopy systems have enabled imaging of entire brain volumes
on the timescale of neural activity and during behavior, enabling the reconstruction of neural circuitry at cellular
resolution. However, recording neural activity from whole brain volumes to reconstruct neural circuitry is a
significant challenge when working with larger brains, less specialized microscopes, or stimuli and behaviors
that are not conducive to concurrent imaging. In these situations, strategies that enable permanent recording
of neural activity during defined time windows for later readout would be highly beneficial.
 In this proposal, we describe an approach for permanent recording of neural activity using Ca2+-dependent
enzymatic activation of genetically encoded substrates. We focus our efforts on the Tobacco Etch Virus (TEV)
protease because it does not have endogenous substrates in vertebrate systems, it has been employed in
living neurons, it has been extensively re-engineered to record interactions between diverse binding partners,
and its split fragments dissociate in the absence of reconstituting binding partners. We propose a strategy for
engineering a Ca2+-dependent TEV protease that involves a split version of the enzyme with each half attached
to the Ca2+-binding partners calmodulin and M13. These TEV fragments are designed so that in the absence of
neural activity they will remain separate and inactive, but in the presence of neural activity and high Ca2+, the
association of calmodulin and M13 will permit TEV reconstitution and enzyme activity. Once active, the split
TEV protease can cleave a variety of genetically encoded substrates that link TEV protease activity with
transcription of a desired gene or direct creation of a fluorophore. Thus, using this strategy will enable users to
control neurons activated by a given stimulus or behavior (e.g., by expressing optogenetic tools in response to
TEV activity) or to visualize neurons active during distinct epochs (e.g., by expressing a photoactivatable
mOrange in response to one stimulus or behavior, photoconverting the mOrange, and then recording the
second stimulus). Finally, the split TEV protease and substrate interactions can be controlled with modular
optogenetics tools to provide precise temporal control over the time period of recording.

## Key facts

- **NIH application ID:** 10133168
- **Project number:** 5R01NS110771-03
- **Recipient organization:** STATE UNIVERSITY NEW YORK STONY BROOK
- **Principal Investigator:** Scott T. Laughlin
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $343,246
- **Award type:** 5
- **Project period:** 2019-04-01 → 2024-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10133168

## Citation

> US National Institutes of Health, RePORTER application 10133168, Opto- and chemogenetic neural activity recording with diverse reporters (5R01NS110771-03). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10133168. Licensed CC0.

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