# Neural coding of leg proprioception

> **NIH NIH R01** · UNIVERSITY OF WASHINGTON · 2020 · $340,156

## Abstract

Project Summary
Proprioception, the sense of self-movement and body position, is critical for the effective control
of motor behavior. Humans lacking proprioceptive feedback, such as patients with peripheral
nerve damage, are unable to maintain limb posture or coordinate fine-scale movements of the
arms and legs. But despite the importance of proprioception to the control of movement in all
animals, little is known about the neural computations that underlie limb proprioception in any
animal. This gap is due to two basic challenges: (1) identifying specific neuronal-cell types that
detect and process proprioceptive signals, and (2) recording neural activity from proprioceptive
circuits during natural limb movements. Here, we propose to overcome these challenges by
investigating the neural coding of leg proprioception in a genetic model organism: the fruit fly,
Drosophila. We have developed new methods to record from genetically-identified neurons in
proprioceptive circuits with in vivo electrophysiology and 2-photon imaging, while
manipulating leg position and movement with a magnetic control system. In Aim 1, we will use
2-photon calcium imaging to define the spatial organization of proprioceptive neural coding
within a population of mechanosensory neurons. In Aim 2, we will use calcium imaging to test
the hypothesis that specific parameters of leg proprioception—such as position and movement—
are encoded by genetically distinct subtypes of mechanosensory neurons. In Aim 3, we will test
the hypothesis that signals from distinct mechanosensory neuron subtypes are integrated by
downstream neurons, using optogenetics and whole-cell patch-clamp electrophysiology.
Altogether, these studies will elucidate basic mechanisms of proprioceptive neural processing
that have not possible to investigate in other systems. Although there are morphological
differences between flies and humans, the basic building blocks of invertebrate and vertebrate
somatosensory systems share a striking evolutionary conservation. These similarities suggest
that the general principles discovered in circuits of the fruit fly will be highly relevant to
somatosensory processing in other animals. A deeper understanding of proprioception has the
potential to transform the way in which we treat somatosensory disorders.

## Key facts

- **NIH application ID:** 9939725
- **Project number:** 5R01NS102333-04
- **Recipient organization:** UNIVERSITY OF WASHINGTON
- **Principal Investigator:** John Tuthill
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $340,156
- **Award type:** 5
- **Project period:** 2017-07-01 → 2022-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9939725

## Citation

> US National Institutes of Health, RePORTER application 9939725, Neural coding of leg proprioception (5R01NS102333-04). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9939725. Licensed CC0.

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