# RP 1: Modeling Forelimb Motor Circuit Organization and Function

> **NIH NIH U19** · SALK INSTITUTE FOR BIOLOGICAL STUDIES · 2023 · $324,693

## Abstract

Project Summary: Project 1 – Modeling Forelimb Motor Circuit Organization and Function
This Research Project addresses the dynamics of motor circuits in the cervical spinal cord. Aims in this project
will analyze how cervical spinal networks coordinate forelimb movement during rhythmic and non-rhythmic
activity. The model will include neuronal elements (excitatory and inhibitory pre-motor neurons and antagonist
pools of motor neurons), antagonist pairs of muscles, and mechanical components of the limb. Theoretical and
computational techniques will be used to describe how these elements interact, including possible responses to
descending brain commands, to generate forelimb activities such as isometric and isotonic movements.
The first goal will be to compute how cervical spinal motor neurons fire in response to inputs (based on slice
electrophysiology experiments, Projects 2 and 3), and how their firing is converted to muscle force (based on
EMG recordings, Project 4). A second goal will be to analyze circuit configurations that achieve maximum control
in order and predict new functional cell types that may be present in the spinal cord. Network models composed
of motor and pre-motor neurons will then be constructed, defining the patterns of network firing and bursting of
antagonistic motor pools, corresponding to elbow and wrist movements and static states. The model will be
constrained by connectivity data (Project 2), and informed by theoretical analyses of optimal circuit configurations.
Finally, a mechanical model of the limb will be connected to the neuronal model to generate a coherent picture
of the transformation from descending input to the cervical spinal cord to limb movements. The dynamical
responses of the model will be compared with the behavioral and in vivo electrophysiological data collected in
Project 4. Overall, the theoretical analyses performed here, together with experimental investigations from
Projects 2-4, will help inform general principles concerning how multiple neuronal types coordinate their response
properties to achieve robust control of multiple dynamical variables.

## Key facts

- **NIH application ID:** 10696192
- **Project number:** 5U19NS112959-05
- **Recipient organization:** SALK INSTITUTE FOR BIOLOGICAL STUDIES
- **Principal Investigator:** Tatyana O. SHARPEE
- **Activity code:** U19 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2023
- **Award amount:** $324,693
- **Award type:** 5
- **Project period:** 2019-09-15 → 2026-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10696192

## Citation

> US National Institutes of Health, RePORTER application 10696192, RP 1: Modeling Forelimb Motor Circuit Organization and Function (5U19NS112959-05). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10696192. Licensed CC0.

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