title: Volitional walking via upper limb muscle-controlled stimulation of the lumbar locomotor center in man.
abstract: Gait disturbance in individuals with spinal cord lesion is attributed to the interruption of descending pathways to the spinal locomotor center, whereas neural circuits below and above the lesion maintain their functional capability. An artificial neural connection (ANC), which bridges supraspinal centers and locomotor networks in the lumbar spinal cord beyond the lesion site, may restore the functional impairment. To achieve an ANC that sends descending voluntary commands to the lumbar locomotor center and bypasses the thoracic spinal cord, upper limb muscle activity was converted to magnetic stimuli delivered noninvasively over the lumbar vertebra. Healthy participants were able to initiate and terminate walking-like behavior and to control the step cycle through an ANC controlled by volitional upper limb muscle activity. The walking-like behavior stopped just after the ANC was disconnected from the participants even when the participant continued to swing arms. Furthermore, additional simultaneous peripheral electrical stimulation to the foot via the ANC enhanced this walking-like behavior. Kinematics of the induced behaviors were identical to those observed in voluntary walking. These results demonstrate that the ANC induces volitionally controlled, walking-like behavior of the legs. This paradigm may be able to compensate for the dysfunction of descending pathways by sending commands to the preserved locomotor center at the lumbar spinal cord and may enable individuals with paraplegia to regain volitionally controlled walking.
authors.affiliation: Department of Developmental Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, 444-8585, Aichi, Japan.
authors.forename: Syusaku
authors.initials: S
authors.lastname: Sasada
authors.affiliation: Department of Developmental Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, 444-8585, Aichi, Japan, Department of Physiological Sciences, School of Life Science, Graduate University for Advanced Studies, SOKENDAI, Hayama, 240-0193, Kanagawa, Japan, Japan Society for the Promotion of Science, Chiyoda 102-8472, Tokyo, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Kato
authors.affiliation: Department of Neurology, School of Medicine, Fukushima Medical University, Fukushima, 960-1295, Japan.
authors.forename: Suguru
authors.initials: S
authors.lastname: Kadowaki
authors.affiliation: Department of Neurology, School of Medicine, Fukushima Medical University, Fukushima, 960-1295, Japan, Department of Neurology, Center for Movement Disorders and Neuromodulation & Institute for Clinical Neuroscience and Medical Psychology, Heinrich-Heine University, Medical Faculty, Düsseldorf, 40233, Germany.
authors.forename: Stefan J
authors.initials: SJ
authors.lastname: Groiss
authors.affiliation: Department of Neurology, School of Medicine, Fukushima Medical University, Fukushima, 960-1295, Japan.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Ugawa
authors.affiliation: Faculty of Education, Chiba University, Chiba, 263-8522, Japan, and.
authors.forename: Tomoyoshi
authors.initials: T
authors.lastname: Komiyama
authors.affiliation: Department of Developmental Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, 444-8585, Aichi, Japan, Department of Physiological Sciences, School of Life Science, Graduate University for Advanced Studies, SOKENDAI, Hayama, 240-0193, Kanagawa, Japan, Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Chiyoda, 102-0076, Tokyo, Japan yukio@nips.ac.jp.
authors.forename: Yukio
authors.initials: Y
authors.lastname: Nishimura
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D004558:Electric Stimulation; D004576:Electromyography; D064368:Healthy Volunteers; D006801:Humans; D008124:Locomotion / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D013119:Spinal Cord Injuries / Q000503:physiopathology; D016138:Walking / Q000502:physiology*
keywords: brain–computer interface; locomotion; spinal cord injury; volitional control; walking