# Develop functional trans-Tango to identify higher-order neurons with determined functions

> **NIH NIH R21** · VIRGINIA POLYTECHNIC INST AND ST UNIV · 2020 · $431,990

## Abstract

A neural circuit is composed of a population of neurons that are interconnected by synapses and carry out a
specific function when activated. Thus, to identify a neural circuit, both the synaptic connections and the func-
tional relevance of each neuron in the circuit must be examined. To date, few methods are available to study
these two aspects of a neural circuit simultaneously. In the current proposal, this problem will be addressed
using a new class of trans-synaptic techniques. Current trans-synaptic techniques enable the labelling of
postsynaptic elements of first-order neurons without using driver lines. However, the ability to discriminate the
function of each neuron in the circuit and the ability to track higher-order neurons remains lacking. A Drosophila
thermosensory system that controls rapid warmth avoidance will be used as a model to demonstrate how a
modified trans-synaptic technique can sparsely label both second- and higher-order neurons in a single neural
circuit and determine their functional relevance to a specific behavioral response. The FLP/FRT recombination
system will be used to sparsely label second- and higher-order neurons. Behavioral assays will be used to dis-
criminate the functions of each labelled neuron. In Aim 1, the current trans-synaptic technique will be combined
with the FLP/FRT recombination system and behavioral assays to sparsely label second-order neurons that are
necessary and sufficient for a specific behavioral response. Aim 2 will use the same strategy as Aim 1 to sparsely
label neurons that control discrete functions and express the trans-synaptic techniques in second-order neurons
to track higher-order neurons. Therefore, in Aim 2, higher-order neurons that are necessary and sufficient for a
specific behavioral response will be sparsely tracked. The expected outcome of this proposal is development of
a tool that can (1) sparsely label synaptically interconnected second- and higher-order neurons without using
driver lines, and (2) determine the function of labelled neurons. The tool will be able to be readily applied to many
other Drosophila neural circuits, where the synaptic connections and the functional relevance of each neuron
will be simultaneously identified. Moreover, it has the potential to provide an alternative for labelling mammalian
circuits.

## Key facts

- **NIH application ID:** 9958274
- **Project number:** 1R21MH122987-01
- **Recipient organization:** VIRGINIA POLYTECHNIC INST AND ST UNIV
- **Principal Investigator:** Lina Ni
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $431,990
- **Award type:** 1
- **Project period:** 2020-04-01 → 2023-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9958274

## Citation

> US National Institutes of Health, RePORTER application 9958274, Develop functional trans-Tango to identify higher-order neurons with determined functions (1R21MH122987-01). Retrieved via AI Analytics 2026-06-12 from https://api.ai-analytics.org/grant/nih/9958274. Licensed CC0.

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