# The Role of M1 Leg Area in Volitional and Stereotyped Control of the Lower Limb

> **NIH VA I01** · PROVIDENCE VA  MEDICAL CENTER · 2024 · —

## Abstract

In the healthy nervous system, the development of intention and motor execution is a dynamic and highly
distributed process that originates in the brain. The intended action is transmitted along the axonal super
highway to smart circuits in the spinal cord that transform the descending command into coordinated patterns
of muscle activation. While much is understood regarding the control strategies the brain uses to drive upper
limb movements, relatively little is known about the central control of human locomotion. Further, failures of
function in one seemingly insignificant processing loop in the brain or periphery can, and often does, lead to
dramatic consequences that induce transient or permanent deficits in motor control. A particularly palpable
example of this is the consequences resulting from spinal cord injury (SCI), which, in extreme cases, can
render a person completely unable to interact with the world around them. Such nervous system injuries and
disorders have long-term health, economic and social consequences in both the civilian and Veteran
population. Despite the best available medical treatments, hundreds of thousands of individuals endure a long
life post-SCI with sensorimotor deficits that dramatically affect their quality of life.
The specific objective of this project is to build fundamental knowledge of how motor cortex (MI) controls
voluntary, as well as stereotypic, lower limb movements, and then to design both a brain-spine interface
leveraging a fully implanted hardware system, as well as a first of its kind end-point brain-machine interface for
lower limb prosthetics. We will study the basic function of nonhuman primate motor cortices during a variety of
hind limb movements, including passive walking on a treadmill, during obstacle avoidance, and direct endpoint
control on a sitting flywheel while recording high-fidelity neural population data and kinematics. Finally, our
results will be interpreted in the context of supporting a translational clinical study in humans to provide a new
rehabilitation pathway for Veterans with spinal injury, as well as neuroprosthetic pathway for amputees. We will
conclusively determine the strategies employed by nonhuman primate motor cortex to both drive and adjust
hind limb placement during locomotion and we will determine if motor cortex activity consequently changes
between so-called “automatic” movements (e.g. walking on a treadmill), and volitional, highly precise
movements (e.g. end-point control on a flywheel).
The proposed study will work with rhesus monkeys trained to walk on an instrumented treadmill, across a flat
corridor, freely within a large naturalistic roaming space, as well as controlling the pedal location along a 2-
dimensional flywheel. Animals will be implanted with a) two silicon microelectrode arrays in MI-leg, and
premotor area (PMd) containing movement planning information; b) an implantable pulse generator connected
to a custom epidural spinal cord stimulatio...

## Key facts

- **NIH application ID:** 11044981
- **Project number:** 5I01RX002835-07
- **Recipient organization:** PROVIDENCE VA  MEDICAL CENTER
- **Principal Investigator:** David Allenson Borton
- **Activity code:** I01 (R01, R21, SBIR, etc.)
- **Funding institute:** VA
- **Fiscal year:** 2024
- **Award amount:** —
- **Award type:** 5
- **Project period:** 2018-11-01 → 2025-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/11044981

## Citation

> US National Institutes of Health, RePORTER application 11044981, The Role of M1 Leg Area in Volitional and Stereotyped Control of the Lower Limb (5I01RX002835-07). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/11044981. Licensed CC0.

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