# Assessment of Chronic Multi-Electrode Spinal Cord Electrical Stimulation and Electromyography Platform in Non-Human Primates

## TL;DR

Researchers developed a platform to monitor spinal cord injury effects in non-human primates using electrical stimulation and muscle activity tracking.

## Contribution

A bioethically acceptable platform for real-time neuromotor monitoring in SCI studies using non-human primates was developed.

## Key findings

- Electrical stimulation at the L2–S1 segments increased hind limb muscle activity and joint movement range.
- SCI caused reduced electromyographic activity and joint movement on the injured side.
- The platform supports pathophysiological studies and development of neurointerfaces.

## Abstract

Background/Objectives: Traumatic spinal cord (SC) injury (SCI) is a debilitating neurological condition. Minimally invasive approaches to monitor in real time the functional state of the neuromotor apparatus in animal models of SCI (at rest and movement) to assess effectiveness of therapy are needed in preclinical studies. We aimed to develop such a bioethically acceptable platform for SCI studies on non-human primates (Rhesus macaques). Methods: Epidural and myographic electrode implantation (EI) (wireless and wired, connected via a head plug) was performed. After EI, motor responses caused by electrical stimulation of the SC at the level of the cervical and lumbar thickening were recorded; electromyography of the limb muscles was recorded during quadrupedal movement of the animal on a treadmill with simultaneous assessment of movements’ kinematic parameters. Five weeks after EI, three animals underwent lateral hemisection of the SC in the C4–C5 segment under the control of a surgical microscope and intraoperative recording of motor- and sensory-evoked potentials. Results: Within 30 days after SCI, during treadmill testing, a decrease in electromyographic activity of the limb muscles and the volume of angular movement in the joints on the side of the injury was detected. Electrical stimulation at the L2–S1 segments of the SC at a frequency of 30 Hz led to the appearance of a locomotor pattern in the muscles of the hind limbs and an increase in the range of motion. Conclusions: Our platform can be used for pathophysiological studies of various neuromodulation modes and as a basis for the development of control neurointerfaces.