# Discovery of sensorimotor connectivity mechanisms in a continuous topographic map

> **NIH NIH R21** · FRED HUTCHINSON CANCER CENTER · 2022 · $244,987

## Abstract

SUMMARY
The long-term goal of this project is to understand the developmental mechanisms underlying neural connectiv-
ity within sensorimotor reflex circuits in our brain. Reflex circuits enable individual sensory inputs to elicit func-
tionally appropriate stereotyped motor outputs, suggesting fine-scale connection specificity between the sensory
and motor systems. However, in the brain, neurons responsible for different functions are often continuously
aligned on topographic maps, with functionally different neurons being intermingled at the boundary regions
between functional groups. It is poorly understood how functionally different neighbors on a topographic map
are distinguished during reflex circuit development so that they can invariably generate appropriate responses
to sensory information. We have established the vagus nerve in larval zebrafish as an efficient system in which
to address this long-standing mystery in brain circuit development. The vagus nerve exits the hindbrain and
branches widely to innervate the pharynx, larynx, stomach, heart and other visceral organs. This nerve carries
both sensory and motor axons, each of which participates in one of several polysynaptic reflex circuits including
the pharyngeal reflex and baroreflex. Our group has discovered that vagus motor neurons and sensory axons are
co-organized in a continuous topographic map that is detectable within the larval zebrafish hindbrain. Our pre-
liminary data support that local sensory inputs to the vagus sensory system selectively activate functionally ap-
propriate groups of vagal motor neurons with a strikingly fine-scale connection specificity that distinguishes
adjacent functionally different neurons. In order to investigate the mechanism underlying this functional sepa-
ration, we will investigate the contribution of neural activity in vagal motor neurons for fine-scale connection
specificity (Aim 1), and we will determine the structural basis of vagal reflex circuit refinement via transsynaptic
labeling (Aim 2). The successful outcome of these aims will provide neurophysiological and neuroanatomical
insights into fine-scale connection specificity at the level of entire sensorimotor reflex circuits in the vertebrate
brain. The larval zebrafish has emerged as a premiere system in which to study developmental neurobiology, and
the tools we develop in the vagus system will be generally applicable to questions about the role of neural activity
in other aspects of nervous system development.

## Key facts

- **NIH application ID:** 10610123
- **Project number:** 6R21NS124191-02
- **Recipient organization:** FRED HUTCHINSON CANCER CENTER
- **Principal Investigator:** Cecilia B Moens
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $244,987
- **Award type:** 6
- **Project period:** 2022-02-01 → 2024-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10610123

## Citation

> US National Institutes of Health, RePORTER application 10610123, Discovery of sensorimotor connectivity mechanisms in a continuous topographic map (6R21NS124191-02). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10610123. Licensed CC0.

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