Probing the Human Spinal Locomotor Circuits by Phasic Step-Induced Feedback and by Tonic Electrical and Pharmacological Neuromodulation.

  title={Probing the Human Spinal Locomotor Circuits by Phasic Step-Induced Feedback and by Tonic Electrical and Pharmacological Neuromodulation.},
  author={Ursula S. Hofstoetter and Maria Knikou and Pierre A. Guertin and Karen Minassian},
  journal={Current pharmaceutical design},
  volume={23 12},
The mammalian lumbar spinal cord experimentally isolated from supraspinal and afferent feedback input remains capable of expressing some basic locomotor function when appropriately stimulated. This ability has been attributed to spinal neural circuits referred to as central pattern generators (CPGs). In individuals with a severe spinal cord injury, rhythmic activity in paralyzed leg muscles can be generated by phasic proprioceptive feedback during therapist- or robotic-assisted stepping on a… 

Spinal Control of Locomotion: Individual Neurons, Their Circuits and Functions

Continuous efforts on the function of spinal interneuronal circuits during mammalian locomotion will assist in delineating the neural mechanisms underlying locomotor control, and help develop novel targeted rehabilitation strategies in cases of impaired bipedal gait in humans.

Neuronal Actions of Transspinal Stimulation on Locomotor Networks and Reflex Excitability During Walking in Humans With and Without Spinal Cord Injury

The soleus H-reflex depression by transspinal stimulation suggests a potential application for normalization of spinal reflex excitability after SCI and is investigated in humans with and without spinal cord injury.

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Repeated transspinal stimulation increases spinal motoneuron responsiveness of ankle and knee muscles in the injured human spinal cord, and thus can promote motor recovery, and is a promising modality for promoting functional neuroplasticity after SCI.

Higher Responsiveness of Pattern Generation Circuitry to Sensory Stimulation in Healthy Humans Is Associated with a Larger Hoffmann Reflex

It is found that the high individual responsiveness of pattern generation circuitries to tonic sensory input in both the upper and lower limbs was related to larger H-reflexes, which is consistent with the idea that spinal reflex measurements play important roles in assessing the rhythmogenesis of the spinal cord.

Repeated transspinal stimulation decreases soleus H-reflex excitability and restores spinal inhibition in human spinal cord injury

The results indicate decreased reflex hyperexcitability and recovery of spinal inhibitory control in the injured human spinal cord with repeated transspinal stimulation.

Epidural and Transcutaneous Spinal Cord Stimulation Strategies for Motor Recovery After Spinal Cord Injury

These neuromodulation therapies provide various perspectives for recovery of motor function in chronic patients in whom limited improvement is expected with standard-of-care rehabilitative options.

The Spinal Control of Backward Locomotion

This paper shows that the center controlling locomotion within the spinal cord can produce a backward pattern when instructed by sensory signals from the limbs, however, the spinal locomotor network requires greater excitability to produce backward locomotion compared with forward locomotion.

Adapting Human-Based Transcutaneous Spinal Cord Stimulation to Develop a Clinically Relevant Animal Model

A new animal model of thoracolumbar tSCS that can accurately recapitulate studies in healthy humans and can receive a repeated and stable t SCS treatment after SCI with minimal restraint is established, and it is shown that the model displays bilateral evoked potentials in multisegmental leg muscles characteristically comparable to humans.

Transcutaneous spinal cord stimulation and motor responses in individuals with spinal cord injury: A methodological review

To establish standardised procedures for neurophysiological assessments and therapeutic investigations of tSCS, further high-quality investigations are required, ideally utilizing consistent electrophysiological recording methods, and reporting common characteristics of the electrical stimulation administered.



Human spinal locomotor control is based on flexibly organized burst generators.

The data imply that the human lumbar spinal cord circuits can form burst-generating elements that flexibly combine to obtain a wide range of locomotor outputs from a constant, repetitive input.

Modelling spinal circuitry involved in locomotor pattern generation: insights from the effects of afferent stimulation

A computational model of the mammalian spinal cord circuitry incorporating a two‐level central pattern generator (CPG) with separate half‐centre rhythm generator (RG) and pattern formation (PF) networks can be integrated with reflex circuits to reproduce the reorganization of group I reflex pathways occurring during locomotion.

Spinal cord pattern generators for locomotion

  • V. Dietz
  • Biology, Psychology
    Clinical Neurophysiology
  • 2003

Spinal Rhythm Generation by Step-Induced Feedback and Transcutaneous Posterior Root Stimulation in Complete Spinal Cord–Injured Individuals

The synergistic effects of these rhythm-generating mechanisms suggest that tSCS in combination with treadmill training might augment rehabilitation outcomes after severe spinal cord injury.

Training locomotor networks

Central pattern generation of locomotion: a review of the evidence.

Evidence for CPGs in humans is reviewed, examples are provided of animal and human studies that apply knowledge of CPG mechanisms to improve locomotion, and future directions in CPG research are addressed.

Transformation of nonfunctional spinal circuits into functional states after the loss of brain input

It is proposed that, in the absence of supraspinal input, spinal locomotion can emerge from a combination of central pattern-generating capability and the ability of these spinal circuits to use sensory afferent input to control stepping.

Closed-loop neuromodulation of spinal sensorimotor circuits controls refined locomotion after complete spinal cord injury

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Transmission in a locomotor-related group Ib pathway from hindlimb extensor muscles in the cat

The above results suggest that the group I input from extensor muscles is transmitted through the spinal rhythm generator and more particularly, through the extensor “half-centre”.