# The organization of spinal neurons following spinal cord injury

> **NIH NIH R01** · TEMPLE UNIV OF THE COMMONWEALTH · 2022 · $460,414

## Abstract

Project Summary/Abstract
Spinal cord injury (SCI) is a life-changing event that sets in motion profound alterations in motor output,
sensory processing, and reflex activity. Immediately following injury there is a depression of motor activity
mediated by a lack of descending drive. In the weeks and months following injury, a reorganization of spinal
neurons (both motoneurons and interneurons) occurs in response to this altered milieu. This includes changes
in the excitability and reorganization of remaining pathways through strengthening of latent connections and
neuronal sprouting. SCI induced changes in the excitability of spinal motoneurons have a profound effect on
their discharge characteristics and ultimately on the generation of muscle force for functional movements. The
reorganization of spinal interneurons is less well understood, even though the overwhelming majority of
synaptic drive to motoneurons is mediated by spinal interneurons. Therefore, this project will explore how
spinal interneurons regulate the discharge of spinal motoneurons. We will combine intraspinal microelectrode
arrays with arrays on the muscle to record the individual discharges of spinal interneuron and motor unit
populations. On these data, we will bring to bear advanced statistical modeling to electrophysiology dissect the
organization of spinal neurons through the quantification of the strength and directional effects of these
excitatory/inhibitory connections. We will use this approach to quantify the organization of spinal neurons in the
intact cord and following either chronic or acute SCI. Further, we will explore the effects of neuromodulation by
targeting specific serotoninergic receptor subtypes. The expected outcome of this work is a new understanding
of the function of the mammalian spinal cord and the capabilities for reorganization of spinal neurons following
both chronic and acute spinal transections. This approach will be a platform for characterizing the synaptic
input from spinal interneurons to motoneurons and how this ultimately produces movement. Our combined
motor unit and interneuron approach will directly quantify the neural substrate underlying motor unit discharge
patterns and will provide a strong basis for motor unit discharge patterns to be a detailed biomarker for
quantifying the state of spinal interneurons in humans with SCI.

## Key facts

- **NIH application ID:** 10340218
- **Project number:** 1R01NS124820-01
- **Recipient organization:** TEMPLE UNIV OF THE COMMONWEALTH
- **Principal Investigator:** Christopher Keith Thompson
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $460,414
- **Award type:** 1
- **Project period:** 2022-02-19 → 2027-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10340218

## Citation

> US National Institutes of Health, RePORTER application 10340218, The organization of spinal neurons following spinal cord injury (1R01NS124820-01). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10340218. Licensed CC0.

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