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Kaneshige M, Obara K, Suzuki M, Tazoe T, Nishimura Y. Tuning of motor outputs produced by spinal stimulation during voluntary control of torque directions in monkeys. eLife 2022; 11:78346. [PMID: 36512395 PMCID: PMC9747157 DOI: 10.7554/elife.78346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 11/25/2022] [Indexed: 12/14/2022] Open
Abstract
Spinal stimulation is a promising method to restore motor function after impairment of descending pathways. While paresis, a weakness of voluntary movements driven by surviving descending pathways, can benefit from spinal stimulation, the effects of descending commands on motor outputs produced by spinal stimulation are unclear. Here, we show that descending commands amplify and shape the stimulus-induced muscle responses and torque outputs. During the wrist torque tracking task, spinal stimulation, at a current intensity in the range of balanced excitation and inhibition, over the cervical enlargement facilitated and/or suppressed activities of forelimb muscles. Magnitudes of these effects were dependent on directions of voluntarily produced torque and positively correlated with levels of voluntary muscle activity. Furthermore, the directions of evoked wrist torque corresponded to the directions of voluntarily produced torque. These results suggest that spinal stimulation is beneficial in cases of partial lesion of descending pathways by compensating for reduced descending commands through activation of excitatory and inhibitory synaptic connections to motoneurons.
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Affiliation(s)
- Miki Kaneshige
- Neural Prosthetics Project, Tokyo Metropolitan Institute of Medical ScienceTokyoJapan,The Japan Society for the Promotion of ScienceTokyoJapan
| | - Kei Obara
- Neural Prosthetics Project, Tokyo Metropolitan Institute of Medical ScienceTokyoJapan,Division of Neural Engineering, Graduate School of Medical and Dental Sciences, Niigata UniversityNiigataJapan
| | - Michiaki Suzuki
- Neural Prosthetics Project, Tokyo Metropolitan Institute of Medical ScienceTokyoJapan
| | - Toshiki Tazoe
- Neural Prosthetics Project, Tokyo Metropolitan Institute of Medical ScienceTokyoJapan
| | - Yukio Nishimura
- Neural Prosthetics Project, Tokyo Metropolitan Institute of Medical ScienceTokyoJapan
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Sasada S, Kadowaki S, Tazoe T, Murayama T, Kato K, Nakao Y, Matsumoto H, Nishimura Y, Ugawa Y. Assessment of safety of self-controlled repetitive trans-vertebral magnetic stimulation. Clin Neurophysiol 2021; 132:3166-3176. [PMID: 34758417 DOI: 10.1016/j.clinph.2021.09.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 08/26/2021] [Accepted: 09/14/2021] [Indexed: 11/29/2022]
Abstract
OBJECTIVE The aim of this study was to assess safety issues of self-controlled repetitive trans-vertebral magnetic stimulation (rTVMS) in humans. METHODS We investigated effects of self-controlled rTVMS (≤20 Hz, ≤90% intensity) on vital signs and subjective sensations in 1690 trials of 30 healthy volunteers and 12 patients with spinal cord disorders. RESULTS Healthy volunteers and the patients received 4595 ± 2345, and 4450 ± 2304 pulses in one day, respectively. No serious adverse events were observed in any participants, and only minor events were seen as follows. While blood pressure was unaffected in the patients, the diastolic blood pressure increased slightly after rTVMS in healthy volunteers. The peripheral capillary oxygen saturation increased after rTVMS in healthy volunteers. "Pain" or "Discomfort" was reported in approximately 10% of trials in both participants groups. Degree of the evoked sensation positively correlated with stimulus intensity and was affected by the site of stimulation. CONCLUSION Self-controlled rTVMS (≤20 Hz and ≤90% intensity) did not induce any serious adverse effects in healthy volunteers and patients with spinal cord disorders. SIGNIFICANCE Our results indicate that rTVMS can be used safely in physiological investigations in healthy volunteers and also as treatment for neurological disorders.
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Affiliation(s)
- Syusaku Sasada
- Department of Developmental Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Aichi, Japan; Department of Food and Nutrition Science, Sagami Women's University, Kanagawa, Japan
| | - Suguru Kadowaki
- Department of Neurology, Ohta General Hospital, Fukushima, Japan
| | - Toshiki Tazoe
- Neural Prosthetics Project, Department of Neuroscience, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Takashi Murayama
- Rehabilitation Therapy, Chiba Rehabilitation Center, Chiba, Japan
| | - Kenji Kato
- Department of Developmental Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Aichi, Japan
| | - Yaoki Nakao
- Department of Developmental Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Aichi, Japan
| | | | - Yukio Nishimura
- Department of Developmental Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Aichi, Japan; Neural Prosthetics Project, Department of Neuroscience, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan; Department of Physiological Sciences, School of Life Science, The Graduate University for Advanced Studies, SOKENDAI, Japan.
| | - Yoshikazu Ugawa
- Department of Human Neurophysiology, School of Medicine, Fukushima Medical University, Fukushima, Japan.
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Kato K, Sawada M, Nishimura Y. Bypassing stroke-damaged neural pathways via a neural interface induces targeted cortical adaptation. Nat Commun 2019; 10:4699. [PMID: 31619680 PMCID: PMC6796004 DOI: 10.1038/s41467-019-12647-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 09/20/2019] [Indexed: 12/03/2022] Open
Abstract
Regaining the function of an impaired limb is highly desirable in paralyzed individuals. One possible avenue to achieve this goal is to bridge the interrupted pathway between preserved neural structures and muscles using a brain–computer interface. Here, we demonstrate that monkeys with subcortical stroke were able to learn to use an artificial cortico-muscular connection (ACMC), which transforms cortical activity into electrical stimulation to the hand muscles, to regain volitional control of a paralysed hand. The ACMC induced an adaptive change of cortical activities throughout an extensive cortical area. In a targeted manner, modulating high-gamma activity became localized around an arbitrarily-selected cortical site controlling stimulation to the muscles. This adaptive change could be reset and localized rapidly to a new cortical site. Thus, the ACMC imparts new function for muscle control to connected cortical sites and triggers cortical adaptation to regain impaired motor function after stroke. Monkeys were trained to use an artificial cortico-muscular connection (ACMC) to regain control over a paralyzed hand following subcortical stroke. Control over the paralyzed hand was accompanied by the appearance of localized high-gamma modulation in the cortex, which could be rapidly reset and relocalized to a different cortical site to reactivate motor control.
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Affiliation(s)
- Kenji Kato
- Department of Developmental Physiology, National Institute for Physiological Sciences, 38 Nishigonaka, Myodaiji, Okazaki, Aichi, 444-8585, Japan.,Department of Physiological Sciences, School of Life Science, The Graduate University for Advanced Studies, SOKENDAI, Shonan Village, Hayama, Kanagawa, 240-0193, Japan.,Japan Society for The Promotion of Science, Kojimachi Business Center Building, 5-3-1 Kojimachi, Chiyoda, Tokyo, 102-0083, Japan.,Center of Assistive Robotics and Rehabilitation for Longevity and Good Health, National Center for Geriatrics and Gerontology, 7-430, Morioka, Obu, Aichi, 474-8511, Japan
| | - Masahiro Sawada
- Department of Developmental Physiology, National Institute for Physiological Sciences, 38 Nishigonaka, Myodaiji, Okazaki, Aichi, 444-8585, Japan.,Department of Neurosurgery, Graduate School of Kyoto University, 54 Shogoin-kawaharacho, Sakyo, Kyoto, 606-8507, Japan
| | - Yukio Nishimura
- Department of Developmental Physiology, National Institute for Physiological Sciences, 38 Nishigonaka, Myodaiji, Okazaki, Aichi, 444-8585, Japan. .,Department of Physiological Sciences, School of Life Science, The Graduate University for Advanced Studies, SOKENDAI, Shonan Village, Hayama, Kanagawa, 240-0193, Japan. .,Neural Prosthesis Project, Department of Dementia and Higher Brain Function, Tokyo Metropolitan Institute of Medical Science, 2-1-6, Kamikitazawa, Setagaya, Tokyo, 158-8506, Japan. .,Department of Neuroscience, Graduate School of Medicine and Faculty of Medicine, Kyoto University, Yoshida-Konoe, Sakyo, Kyoto, 606-8501, Japan. .,Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Sanban-tyo, Chiyoda, Tokyo, 102-0076, Japan.
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