# Presynaptic partners of corticospinal neurons to control skilled movements

> **NIH NIH R01** · WINIFRED MASTERSON BURKE MED RES INST · 2020 · $580,582

## Abstract

The highly orchestrated muscle activation sequences during motor behaviors are
achieved directly through the fine-tuned firing of motor neurons in the ventral spinal cord. These motor
neurons are mainly regulated by spinal interneurons present in all mammals, which are, in turn, connected to
other spinal neurons as well as various types of descending neurons from the brain including corticospinal
(CS) neurons (CSNs). CSNs located in the motor cortex connect to spinal interneurons to control motor
neuron activity in all species, and thereby coordinate the activity of flexor and extensor limb muscles to control
skilled movements. Although we and others mainly focused on outputs of CSNs through their axons, CSNs
also receive inputs from their presynaptic neurons through their dendrites. However, the identification and
understanding of the function of presynaptic neurons of CSNs (pre-CSNs) remains limited. We developed
rabies virus-based assays to identify pre-CSNs. We hypothesize that each population of pre-CSNs will be
distinctly activated to control discrete phases of skilled movements and muscle activation. To test our
hypothesis, in Aim 1 we will map presynaptic partners of CSNs in the brain. We will further determine whether
those connections are functional (Aim 2). Finally, we will determine how pre-CSNs control forelimb skilled
movements and muscle activity (Aim 3). These results will provide the necessary framework for not only
defining spinal motor circuitry, but also subsequent development of novel targeted interventions to treat motor
disabilities.

## Key facts

- **NIH application ID:** 10050580
- **Project number:** 2R01NS093002-07
- **Recipient organization:** WINIFRED MASTERSON BURKE MED RES INST
- **Principal Investigator:** Yutaka Yoshida
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $580,582
- **Award type:** 2
- **Project period:** 2015-09-15 → 2025-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10050580

## Citation

> US National Institutes of Health, RePORTER application 10050580, Presynaptic partners of corticospinal neurons to control skilled movements (2R01NS093002-07). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10050580. Licensed CC0.

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