# Corticospinal control of spinal reflex plasticity

> **NIH VA I01** · STRATTON VETERANS ADMIN MEDICAL CENTER · 2021 · —

## Abstract

Spinal cord injury (SCI), traumatic brain injury, stroke, multiple sclerosis, and other chronic disorders
produce abnormal reflexes that impair locomotion, reach-and-grasp, and other motor functions for millions of
Americans, including many Veterans. New treatments are urgently needed. Operant conditioning protocols can
change spinal reflexes in rats, mice, monkeys, and people. These protocols, which are non-invasive in
humans, can target beneficial plasticity to a specific reflex pathway. The reflex is elicited and the subject is
rewarded if the reflex satisfies a size criterion. The subject learns to modify corticospinal control over the
pathway. This control gradually changes the spinal pathway itself, and thereby triggers further beneficial
plasticity elsewhere. In people with incomplete SCI, operant conditioning of the soleus H-reflex increases
walking speed and reduces limping. The improvements persist; they are apparent to people in their daily lives.
 {Reflex conditioning in people with SCI or stroke now requires 36 one-hr sessions over 12 weeks, and
is successful in only 50-70%.} Better understanding of the cortical activity that drives the reflex change should
lead to better protocols that increase the reliability, magnitude, and speed of reflex conditioning, and thereby
enhance its clinical value. This project seeks to identify electroencephalographic (EEG) features that reflect the
crucial cortical activity, to use these features to improve the reflex conditioning protocol, {and to show that this
protocol is effective in Veterans with chronic stroke.} It has two specific aims.
 Aim 1 will identify EEG features that correlate will the size of the H-reflex in the arm muscle flexor carpi
radialis (FCR) and incorporate these features into the operant conditioning protocol. Based on human and
animal data, we expect that the best feature will be sensorimotor rhythm (SMR) amplitude over contralateral
sensorimotor cortex (SMC) in the 1 sec immediately before H-reflex elicitation. The new protocol will require
that this EEG feature satisfy a size criterion prior to H-reflex elicitation. We expect that this new requirement
will guide the person to produce, maximize, and maintain appropriate change in corticospinal influence on the
reflex pathway; it will thereby increase the reliability, magnitude, and speed of H-reflex change. We will develop
and validate this new protocol through studies in Veterans without neurological disease.
 {Aim 2 will recruit Veterans with impaired arm function due to a stroke >1 yr earlier. One group will
undergo FCR H-reflex down-conditioning with the enhanced protocol; another group will undergo down-
conditioning with the standard protocol. (We will down-condition the FCR H-reflex in these Veterans because it
is the down-conditioning protocol that would be used clinically to reduce the hyperreflexia and/or the abnormal
flexor synergy than can occur with stroke.) Because the enhanced protocol will guide the person t...

## Key facts

- **NIH application ID:** 10041767
- **Project number:** 5I01CX001812-03
- **Recipient organization:** STRATTON VETERANS ADMIN MEDICAL CENTER
- **Principal Investigator:** Jonathan Rickel Wolpaw
- **Activity code:** I01 (R01, R21, SBIR, etc.)
- **Funding institute:** VA
- **Fiscal year:** 2021
- **Award amount:** —
- **Award type:** 5
- **Project period:** 2018-10-01 → 2022-09-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10041767

## Citation

> US National Institutes of Health, RePORTER application 10041767, Corticospinal control of spinal reflex plasticity (5I01CX001812-03). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10041767. Licensed CC0.

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