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Kinany N, Khatibi A, Lungu O, Finsterbusch J, Büchel C, Marchand-Pauvert V, Ville DVD, Vahdat S, Doyon J. Decoding cerebro-spinal signatures of human behavior: application to motor sequence learning. Neuroimage 2023; 275:120174. [PMID: 37201642 DOI: 10.1016/j.neuroimage.2023.120174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 05/12/2023] [Accepted: 05/15/2023] [Indexed: 05/20/2023] Open
Abstract
Mapping the neural patterns that drive human behavior is a key challenge in neuroscience. Even the simplest of our everyday actions stem from the dynamic and complex interplay of multiple neural structures across the central nervous system (CNS). Yet, most neuroimaging research has focused on investigating cerebral mechanisms, while the way the spinal cord accompanies the brain in shaping human behavior has been largely overlooked. Although the recent advent of functional magnetic resonance imaging (fMRI) sequences that can simultaneously target the brain and spinal cord has opened up new avenues for studying these mechanisms at multiple levels of the CNS, research to date has been limited to inferential univariate techniques that cannot fully unveil the intricacies of the underlying neural states. To address this, we propose to go beyond traditional analyses and instead use a data-driven multivariate approach leveraging the dynamic content of cerebro-spinal signals using innovation-driven coactivation patterns (iCAPs). We demonstrate the relevance of this approach in a simultaneous brain-spinal cord fMRI dataset acquired during motor sequence learning (MSL), to highlight how large-scale CNS plasticity underpins rapid improvements in early skill acquisition and slower consolidation after extended practice. Specifically, we uncovered cortical, subcortical and spinal functional networks, which were used to decode the different stages of learning with a high accuracy and, thus, delineate meaningful cerebro-spinal signatures of learning progression. Our results provide compelling evidence that the dynamics of neural signals, paired with a data-driven approach, can be used to disentangle the modular organization of the CNS. While we outline the potential of this framework to probe the neural correlates of motor learning, its versatility makes it broadly applicable to explore the functioning of cerebro-spinal networks in other experimental or pathological conditions.
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Affiliation(s)
- N Kinany
- Department of Radiology and Medical Informatics, University of Geneva, Geneva, 1211, Switzerland; Neuro-X Institute, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, 1202, Switzerland.
| | - A Khatibi
- Center of Precision Rehabilitation for Spinal Pain, School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, B15 2TT, United Kingdom
| | - O Lungu
- McConnell Brain Imaging Center, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - J Finsterbusch
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Germany
| | - C Büchel
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Germany
| | - V Marchand-Pauvert
- Sorbonne Université, Inserm, CNRS, Laboratoire d'Imagerie biomédicale, Paris F-75006, France
| | - D Van De Ville
- Department of Radiology and Medical Informatics, University of Geneva, Geneva, 1211, Switzerland; Neuro-X Institute, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, 1202, Switzerland
| | - S Vahdat
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, FL 32611, United States
| | - J Doyon
- McConnell Brain Imaging Center, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
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Yang L, Martin JH. Effects of motor cortex neuromodulation on the specificity of corticospinal tract spinal axon outgrowth and targeting in rats. Brain Stimul 2023; 16:759-771. [PMID: 37094762 PMCID: PMC10501380 DOI: 10.1016/j.brs.2023.04.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Revised: 04/01/2023] [Accepted: 04/19/2023] [Indexed: 04/26/2023] Open
Abstract
BACKGROUND Neural activity helps construct neural circuits during development and this function is leveraged by neuromodulation protocols to promote connectivity and repair in maturity. Neuromodulation targeting the motor cortex (MCX) strengthens connections for evoking muscle contraction (MEPs). Mechanisms include promoting local MCX and corticospinal tract (CST) synaptic efficacy and also axon terminal structural changes. OBJECTIVE In this study, we address the question of potential causality between neuronal activation and the neuronal structural response. METHODS We used patterned optogenetic activation (ChR2-EYFP), daily for 10-days, to deliver intermittent theta burst stimulation (iTBS) to activate MCX neurons within the forelimb representation in healthy rats, while differentiating them from neurons in the same population that were not activated. We used chemogenetic DREADD activation to produce a daily period of non-patterned neuronal activation. RESULTS We found a significant increase in CST axon length, axon branching, contacts targeted to a class of premotor interneuron (Chx10), as well as projections into the motor pools in the ventral horn in optically activated but not neighboring non-activated neurons. A period of 2-h of continuous activation daily for 10 days using DREADD chemogenetic activation with systemic clozapine N-oxide (CNO) administration also increased CST axon length and branching, but not the ventral horn and Chx10 targeting effects. Both patterned optical and chemogenetic activation reduced MCX MEP thresholds. CONCLUSION Our findings show that targeting of CST axon sprouting is dependent on patterned activation, but that CST spinal axon outgrowth and branching are not. Our optogenetic findings, by distinguishing optically activated and non-activated CST axons, suggests that the switch for activity-dependent axonal outgrowth is neuron-intrinsic.
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Affiliation(s)
- Lillian Yang
- Department of Molecular, Cellular, and Biomedical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, USA
| | - John H Martin
- Department of Molecular, Cellular, and Biomedical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, USA; Neuroscience Program, Graduate Center of the City University of New York, New York, NY, USA.
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3
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Amer A, Martin JH. Repeated motor cortex theta-burst stimulation produces persistent strengthening of corticospinal motor output and durable spinal cord structural changes in the rat. Brain Stimul 2022; 15:1013-1022. [PMID: 35850438 PMCID: PMC10164459 DOI: 10.1016/j.brs.2022.07.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 06/29/2022] [Accepted: 07/12/2022] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND The strength of connections between motor cortex (MCX) and muscle can be augmented with a variety of stimulation protocols. Augmenting MCX-to-muscle connection strength by neuromodulation may be a way to enhance the intact motor system's capacity for acquiring motor skills and promote function after injury to strengthen spared connections. But this enhancement must be maintained for functional improvements. OBJECTIVE We determined if brief MCX muscle evoked potential (MEP) enhancement produced by intermittent theta burst stimulation (iTBS) can be converted into a longer and structurally durable form of response enhancement with repeated daily and longer-term application. METHODS Electrical iTBS was delivered through an implanted MCX epidural electrode and MEPs were recorded using implanted EMG electrodes in awake naïve rats. MCX activity was modulated further using chemogenetic (DREADDs) excitation and inhibition. Corticospinal tract (CST) axons were traced and immunochemistry used to measure CST synapses. RESULTS A single MCX iTBS block (600 pulses) produced MEP LTP lasting ∼30-45 min. Concatenating five iTBS blocks within a 30-min session produced MEP LTP lasting 24-48 h, which could be strengthened or weakened by bidirectional MCX activity modulation. Effect duration was not changed. Finally, daily induction of this persistent MEP LTP with daily iTBS for 10-days produced MEP enhancement outlasting the stimulation period by at least 10 days, and accompanied by CST axonal outgrowth and structural changes at the CST-spinal interneuron synapse. CONCLUSION Our findings inform the mechanisms of iTBS and provide a framework for designing neuromodulatory strategies to promote durable enhancement of cortical motor actions.
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Affiliation(s)
- Alzahraa Amer
- Department of Molecular, Cellular, and Biomedical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, USA; Neuroscience Program, Graduate Center of the City University of New York, New York, NY, USA
| | - John H Martin
- Department of Molecular, Cellular, and Biomedical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, USA; Neuroscience Program, Graduate Center of the City University of New York, New York, NY, USA.
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4
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Solopova IA, Selionov VA, Blinov EO, Dolinskaya IY, Zhvansky DS, Lacquaniti F, Ivanenko Y. Higher Responsiveness of Pattern Generation Circuitry to Sensory Stimulation in Healthy Humans Is Associated with a Larger Hoffmann Reflex. BIOLOGY 2022; 11:biology11050707. [PMID: 35625435 PMCID: PMC9138260 DOI: 10.3390/biology11050707] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 04/26/2022] [Accepted: 05/02/2022] [Indexed: 11/25/2022]
Abstract
Simple Summary Individual differences in the sensorimotor circuitry play an important role for understanding the nature of behavioral variability and developing personalized therapies. While the spinal network likely requires relatively rigid organization, it becomes increasingly evident that adaptability and inter-individual variability in the functioning of the neuronal circuitry is present not only in the brain but also in the spinal cord. In this study we investigated the relationship between the excitability of pattern generation circuitry and segmental reflexes in healthy humans. We 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. The results provide further evidence for the importance of physiologically relevant assessments of spinal cord neuromodulation and the individual physiological state of reflex pathways. Abstract The state and excitability of pattern generators are attracting the increasing interest of neurophysiologists and clinicians for understanding the mechanisms of the rhythmogenesis and neuromodulation of the human spinal cord. It has been previously shown that tonic sensory stimulation can elicit non-voluntary stepping-like movements in non-injured subjects when their limbs were placed in a gravity-neutral unloading apparatus. However, large individual differences in responsiveness to such stimuli were observed, so that the effects of sensory neuromodulation manifest only in some of the subjects. Given that spinal reflexes are an integral part of the neuronal circuitry, here we investigated the extent to which spinal pattern generation excitability in response to the vibrostimulation of muscle proprioceptors can be related to the H-reflex magnitude, in both the lower and upper limbs. For the H-reflex measurements, three conditions were used: stationary limbs, voluntary limb movement and passive limb movement. The results showed that the H-reflex was considerably higher in the group of participants who demonstrated non-voluntary rhythmic responses than it was in the participants who did not demonstrate them. Our findings are consistent with the idea that spinal reflex measurements play important roles in assessing the rhythmogenesis of the spinal cord.
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Affiliation(s)
- Irina A. Solopova
- Laboratory of Neurobiology of Motor Control, Institute for Information Transmission Problems, Russian Academy of Sciences, 127951 Moscow, Russia; (I.A.S.); (V.A.S.); (I.Y.D.); (D.S.Z.)
| | - Victor A. Selionov
- Laboratory of Neurobiology of Motor Control, Institute for Information Transmission Problems, Russian Academy of Sciences, 127951 Moscow, Russia; (I.A.S.); (V.A.S.); (I.Y.D.); (D.S.Z.)
| | - Egor O. Blinov
- School of Biological and Medical Physics, Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia;
| | - Irina Y. Dolinskaya
- Laboratory of Neurobiology of Motor Control, Institute for Information Transmission Problems, Russian Academy of Sciences, 127951 Moscow, Russia; (I.A.S.); (V.A.S.); (I.Y.D.); (D.S.Z.)
- School of Biological and Medical Physics, Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia;
| | - Dmitry S. Zhvansky
- Laboratory of Neurobiology of Motor Control, Institute for Information Transmission Problems, Russian Academy of Sciences, 127951 Moscow, Russia; (I.A.S.); (V.A.S.); (I.Y.D.); (D.S.Z.)
| | - Francesco Lacquaniti
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, 00179 Rome, Italy;
- Department of Systems Medicine and Center of Space Biomedicine, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Yury Ivanenko
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, 00179 Rome, Italy;
- Correspondence:
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Khatibi A, Vahdat S, Lungu O, Finsterbusch J, Büchel C, Cohen-Adad J, Marchand-Pauvert V, Doyon J. Brain-spinal cord interaction in long-term motor sequence learning in human: An fMRI study. Neuroimage 2022; 253:119111. [PMID: 35331873 DOI: 10.1016/j.neuroimage.2022.119111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 03/03/2022] [Accepted: 03/16/2022] [Indexed: 10/18/2022] Open
Abstract
The spinal cord is important for sensory guidance and execution of skilled movements. Yet its role in human motor learning is not well understood. Despite evidence revealing an active involvement of spinal circuits in the early phase of motor learning, whether long-term learning engages similar changes in spinal cord activation and functional connectivity remains unknown. Here, we investigated spinal-cerebral functional plasticity associated with learning of a specific sequence of visually-guided joystick movements (sequence task) over six days of training. On the first and last training days, we acquired high-resolution functional images of the brain and cervical cord simultaneously, while participants practiced the sequence or a random task while electromyography was recorded from wrist muscles. After six days of training, the subjects' motor performance improved in the sequence compared to the control condition. These behavioral changes were associated with decreased co-contractions and increased reciprocal activations between antagonist wrist muscles. Importantly, early learning was characterized by activation in the C8 level, whereas a more rostral activation in the C6-C7 was found during the later learning phase. Motor sequence learning was also supported by increased spinal cord functional connectivity with distinct brain networks, including the motor cortex, superior parietal lobule, and the cerebellum at the early stage, and the angular gyrus and cerebellum at a later stage of learning. Our results suggest that the early vs. late shift in spinal activation from caudal to rostral cervical segments synchronized with distinct brain networks, including parietal and cerebellar regions, is related to progressive changes reflecting the increasing fine control of wrist muscles during motor sequence learning.
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Affiliation(s)
- Ali Khatibi
- McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, QC, Canada; Centre de recherche de l'Institut Universitaire de Gériatrie de Montréal, Montréal, QC, Canada; Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), University of Birmingham, UK; Centre for Human Brain Health, University of Birmingham, UK.
| | - Shahabeddin Vahdat
- McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, QC, Canada; Centre de recherche de l'Institut Universitaire de Gériatrie de Montréal, Montréal, QC, Canada; Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Ovidiu Lungu
- McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, QC, Canada; Centre de recherche de l'Institut Universitaire de Gériatrie de Montréal, Montréal, QC, Canada; Department of psychiatry and addictology, University of Montreal, Montreal, QC, Canada
| | - Jurgen Finsterbusch
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Germany
| | - Christian Büchel
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Germany
| | - Julien Cohen-Adad
- NeuroPoly Lab, Institute of Biomedical Engineering, Polytechnique Montreal, Montreal, QC, Canada; Functional Neuroimaging Unit, CRIUGM, University of Montreal, Montreal, QC, Canada; Mila Quebec AI Institute, Montreal, QC, Canada
| | | | - Julien Doyon
- McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, QC, Canada; Centre de recherche de l'Institut Universitaire de Gériatrie de Montréal, Montréal, QC, Canada
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Abstract
The sudden loss of movement after spinal cord injury (SCI) is life-changing and is a major impetus to study spinal cord motor system plasticity and devise novel repair strategies. This review focuses on the motor cortex and the corticospinal tract, which are key to producing voluntary movements. The motor cortex projects directly to the spinal cord, via the corticospinal tract, and indirectly, via relays in the brain stem. With loss of the corticospinal tract after SCI, the indirect paths may bypass the injury and play an important role in voluntary control. In health and after injury, the spinal cord is a key site for activity-dependent neuroplasticity of the corticospinal system. Three kinds of activity-dependent plasticity have been identified: (1) corticospinal tract axon sprouting after electrical stimulation of the motor cortex; (2) synaptic competition between corticospinal tract and proprioceptive afferent fiber terminations; and (3) long-term potentiation (LTP) at the corticospinal tract-spinal interneuron synapse. SCI damages descending motor pathway connections and, in turn, triggers a loss of down-stream activity-dependent processes. This activity loss produces spinal interneuron degeneration and several activity-dependent maladaptive changes that underly hyperreflexia, spasticity, and spasms. Animal studies show that phasic electrical and tonic direct current stimulation can be used to supplement activity after SCI to reduce the activity-dependent degenerative and maladaptive changes. Importantly, when applied chronically neuromodulation recruits spinal neuroplasticity to improve function after SCI by promoting activity-dependent corticospinal axon sprouting and synapse formation. This helps establish new functional connections and strengthens spared connections. Combining neuromodulation to promote repair and motor rehabilitation to train circuits can most effectively promote motor recovery.
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Affiliation(s)
- John H Martin
- Department of Molecular, Cellular, and Biomedical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, United States; Neuroscience Program, Graduate Center of the City University of New York, New York, NY, United States.
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7
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Bertschinger R, Giboin LS, Gruber M. Endurance Trained Athletes Do Not per se Have Higher Hoffmann Reflexes Than Recreationally Active Controls. Front Physiol 2021; 12:736067. [PMID: 34867445 PMCID: PMC8633408 DOI: 10.3389/fphys.2021.736067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Accepted: 10/21/2021] [Indexed: 11/13/2022] Open
Abstract
The impact of endurance training on spinal neural circuitries remains largely unknown. Some studies have reported higher H-reflexes in endurance trained athletes and therefore, adaptations within the Ia afferent pathways after long term endurance training have been suggested. In the present study we tested the hypothesis that cyclists (n = 12) demonstrate higher Hoffmann reflexes (H-reflexes) compared to recreationally active controls (n = 10). Notwithstanding, highly significant differences in endurance performance (VO2peak: 60.6 for cyclists vs. 46.3 ml/min/kg for controls (p < 0.001) there was no difference in the size of the SOL H-reflex between cyclists and controls (Hmax/Mmax ratio 61.3 vs. 60.0%, respectively (p = 0.840). Further analyses of the H and M recruitment curves for SOL revealed a significant steeper slope of the M recruitment curve in the group of cyclists (76.2 ± 3.8° vs. 72.0 ± 4.4°, p = 0.046) without a difference in the H-recruitment curve (84.6 ± 3.0° vs. 85.0 ± 2.8°, p = 0.784) compared to the control group. Cycling is classified as an endurance sport and thus the findings of the present study do not further support the assumption that long-term aerobic training leads to a general increase of the H-reflex. Amongst methodological differences in assessing the H-reflex, the training-specific sensorimotor control of the endurance sport itself might differently affect the responsiveness of spinal motoneurons on Ia-afferent inputs.
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Affiliation(s)
- Raphael Bertschinger
- Human Performance Research Centre, Department of Sport Science, University of Konstanz, Konstanz, Germany
| | - Louis-Solal Giboin
- Human Performance Research Centre, Department of Sport Science, University of Konstanz, Konstanz, Germany
| | - Markus Gruber
- Human Performance Research Centre, Department of Sport Science, University of Konstanz, Konstanz, Germany
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Christiansen L, Larsen MN, Madsen MJ, Grey MJ, Nielsen JB, Lundbye-Jensen J. Long-term motor skill training with individually adjusted progressive difficulty enhances learning and promotes corticospinal plasticity. Sci Rep 2020; 10:15588. [PMID: 32973251 PMCID: PMC7518278 DOI: 10.1038/s41598-020-72139-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 08/21/2020] [Indexed: 12/16/2022] Open
Abstract
Motor skill acquisition depends on central nervous plasticity. However, behavioural determinants leading to long lasting corticospinal plasticity and motor expertise remain unexplored. Here we investigate behavioural and electrophysiological effects of individually tailored progressive practice during long-term motor skill training. Two groups of participants practiced a visuomotor task requiring precise control of the right digiti minimi for 6 weeks. One group trained with constant task difficulty, while the other group trained with progressively increasing task difficulty, i.e. continuously adjusted to their individual skill level. Compared to constant practice, progressive practice resulted in a two-fold greater performance at an advanced task level and associated increases in corticospinal excitability. Differences were maintained 8 days later, whereas both groups demonstrated equal retention 14 months later. We demonstrate that progressive practice enhances motor skill learning and promotes corticospinal plasticity. These findings underline the importance of continuously challenging patients and athletes to promote neural plasticity, skilled performance, and recovery.
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Affiliation(s)
- Lasse Christiansen
- Department of Nutrition Exercise and Sports, University of Copenhagen, Copenhagen, Denmark. .,Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital, Amager and Hvidovre, Hvidovre, Denmark.
| | - Malte Nejst Larsen
- Department of Nutrition Exercise and Sports, University of Copenhagen, Copenhagen, Denmark.,Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Mads Just Madsen
- Department of Nutrition Exercise and Sports, University of Copenhagen, Copenhagen, Denmark.,Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital, Amager and Hvidovre, Hvidovre, Denmark
| | - Michael James Grey
- School of Health Sciences, Faculty of Medicine and Health Sciences, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
| | - Jens Bo Nielsen
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | - Jesper Lundbye-Jensen
- Department of Nutrition Exercise and Sports, University of Copenhagen, Copenhagen, Denmark.,Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
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Cappellini G, Sylos-Labini F, Dewolf AH, Solopova IA, Morelli D, Lacquaniti F, Ivanenko Y. Maturation of the Locomotor Circuitry in Children With Cerebral Palsy. Front Bioeng Biotechnol 2020; 8:998. [PMID: 32974319 PMCID: PMC7462003 DOI: 10.3389/fbioe.2020.00998] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 07/30/2020] [Indexed: 12/26/2022] Open
Abstract
The first years of life represent an important phase of maturation of the central nervous system, processing of sensory information, posture control and acquisition of the locomotor function. Cerebral palsy (CP) is the most common group of motor disorders in childhood attributed to disturbances in the fetal or infant brain, frequently resulting in impaired gait. Here we will consider various findings about functional maturation of the locomotor output in early infancy, and how much the dysfunction of gait in children with CP can be related to spinal neuronal networks vs. supraspinal dysfunction. A better knowledge about pattern generation circuitries in infancy may improve our understanding of developmental motor disorders, highlighting the necessity for regulating the functional properties of abnormally developed neuronal locomotor networks as a target for early sensorimotor rehabilitation. Various clinical approaches and advances in biotechnology are also considered that might promote acquisition of the locomotor function in infants at risk for locomotor delays.
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Affiliation(s)
- Germana Cappellini
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, Rome, Italy.,Department of Pediatric Neurorehabilitation, IRCCS Santa Lucia Foundation, Rome, Italy
| | | | - Arthur H Dewolf
- Centre of Space Bio-medicine and Department of Systems Medicine, University of Rome "Tor Vergata", Rome, Italy
| | - Irina A Solopova
- Laboratory of Neurobiology of Motor Control, Institute for Information Transmission Problems, Moscow, Russia
| | - Daniela Morelli
- Department of Pediatric Neurorehabilitation, IRCCS Santa Lucia Foundation, Rome, Italy
| | - Francesco Lacquaniti
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, Rome, Italy.,Centre of Space Bio-medicine and Department of Systems Medicine, University of Rome "Tor Vergata", Rome, Italy
| | - Yury Ivanenko
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, Rome, Italy
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10
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Button DC, Kalmar JM. Understanding exercise-dependent plasticity of motoneurons using intracellular and intramuscular approaches. Appl Physiol Nutr Metab 2019; 44:1125-1133. [PMID: 31075205 DOI: 10.1139/apnm-2018-0862] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Spinal motoneurons (MN) exhibit exercise-dependent adaptations to increased activity, such as exercise and locomotion, as well as decreased activity associated with disuse, spinal cord injury, and aging. The development of several experimental approaches, in both human and animal models, has contributed significantly to our understanding of this plasticity. The purpose of this review is to summarize how intracellular recordings in an animal model and motor unit recordings in a human model have, together, contributed to our current understanding of exercise-dependent MN plasticity. These approaches and techniques will allow neuroscientists to continue to advance our understanding of MN physiology and the plasticity of the "final common path" of the motor system, and to design experiments to answer the critical questions that are emerging in this field.
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Affiliation(s)
- Duane C Button
- School of Human Kinetics and Recreation and BioMedical Sciences, Faculty of Medicine, Memorial University, St. John's, NL A1C 5S7, Canada
| | - Jayne M Kalmar
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, Waterloo, ON N2L 3C5, Canada
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11
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Wolpaw JR. The negotiated equilibrium model of spinal cord function. J Physiol 2018; 596:3469-3491. [PMID: 29663410 PMCID: PMC6092289 DOI: 10.1113/jp275532] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 04/05/2018] [Indexed: 12/25/2022] Open
Abstract
The belief that the spinal cord is hardwired is no longer tenable. Like the rest of the CNS, the spinal cord changes during growth and ageing, when new motor behaviours are acquired, and in response to trauma and disease. This paper describes a new model of spinal cord function that reconciles its recently appreciated plasticity with its long-recognized reliability as the final common pathway for behaviour. According to this model, the substrate of each motor behaviour comprises brain and spinal plasticity: the plasticity in the brain induces and maintains the plasticity in the spinal cord. Each time a behaviour occurs, the spinal cord provides the brain with performance information that guides changes in the substrate of the behaviour. All the behaviours in the repertoire undergo this process concurrently; each repeatedly induces plasticity to preserve its key features despite the plasticity induced by other behaviours. The aggregate process is a negotiation among the behaviours: they negotiate the properties of the spinal neurons and synapses that they all use. The ongoing negotiation maintains the spinal cord in an equilibrium - a negotiated equilibrium - that serves all the behaviours. This new model of spinal cord function is supported by laboratory and clinical data, makes predictions borne out by experiment, and underlies a new approach to restoring function to people with neuromuscular disorders. Further studies are needed to test its generality, to determine whether it may apply to other CNS areas such as the cerebral cortex, and to develop its therapeutic implications.
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Affiliation(s)
- Jonathan R. Wolpaw
- National Center for Adaptive Neurotechnologies, Wadsworth CenterNYS Department of HealthAlbanyNYUSA
- Department of NeurologyStratton VA Medical CenterAlbanyNYUSA
- Department of Biomedical SciencesSchool of Public HealthSUNY AlbanyNYUSA
- Department of Neurology, Neurological InstituteColumbia UniversityNew YorkNYUSA
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