title: The Human Central Pattern Generator for Locomotion: Does It Exist and Contribute to Walking?
abstract: The ability of dedicated spinal circuits, referred to as central pattern generators (CPGs), to produce the basic rhythm and neural activation patterns underlying locomotion can be demonstrated under specific experimental conditions in reduced animal preparations. The existence of CPGs in humans is a matter of debate. Equally elusive is the contribution of CPGs to normal bipedal locomotion. To address these points, we focus on human studies that utilized spinal cord stimulation or pharmacological neuromodulation to generate rhythmic activity in individuals with spinal cord injury, and on neuromechanical modeling of human locomotion. In the absence of volitional motor control and step-specific sensory feedback, the human lumbar spinal cord can produce rhythmic muscle activation patterns that closely resemble CPG-induced neural activity of the isolated animal spinal cord. In this sense, CPGs in humans can be defined by the activity they produce. During normal locomotion, CPGs could contribute to the activation patterns during specific phases of the step cycle and simplify supraspinal control of step cycle frequency as a feedforward component to achieve a targeted speed. Determining how the human CPGs operate will be essential to advance the theory of neural control of locomotion and develop new locomotor neurorehabilitation paradigms.
authors.affiliation: 1 Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.|2 Center for Medical Physics and Biomedical Engineering, Medical University Vienna, Vienna, Austria.
authors.forename: Karen
authors.initials: K
authors.lastname: Minassian
authors.affiliation: 2 Center for Medical Physics and Biomedical Engineering, Medical University Vienna, Vienna, Austria.
authors.forename: Ursula S
authors.initials: US
authors.lastname: Hofstoetter
authors.affiliation: 3 Biorobotics Laboratory, School of Engineering, Institute of Bioengineering, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.
authors.forename: Florin
authors.initials: F
authors.lastname: Dzeladini
authors.affiliation: 4 Department of Psychiatry & Neurosciences, Laval University, Québec City, Quebec, Canada.
authors.forename: Pierre A
authors.initials: PA
authors.lastname: Guertin
authors.affiliation: 3 Biorobotics Laboratory, School of Engineering, Institute of Bioengineering, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.
authors.forename: Auke
authors.initials: A
authors.lastname: Ijspeert
mesh_terms: D000818:Animals; D063226:Central Pattern Generators / Q000502:physiology*; D006801:Humans; D008124:Locomotion / Q000502:physiology*; D008959:Models, Neurological; D013116:Spinal Cord / Q000502:physiology; D013119:Spinal Cord Injuries / Q000503:physiopathology
keywords: CPG; central pattern generator; human; locomotion; modelling; neuromodulation; spinal cord; spinal cord injury; spinal cord stimulation