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Mohammadshirazi A, Apicella R, Zylberberg BA, Mazzone GL, Taccola G. Suprapontine Structures Modulate Brainstem and Spinal Networks. Cell Mol Neurobiol 2023:10.1007/s10571-023-01321-z. [PMID: 36732488 DOI: 10.1007/s10571-023-01321-z] [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: 11/25/2022] [Accepted: 01/19/2023] [Indexed: 02/04/2023]
Abstract
Several spinal motor output and essential rhythmic behaviors are controlled by supraspinal structures, although their contribution to neuronal networks for respiration and locomotion at birth still requires better characterization. As preparations of isolated brainstem and spinal networks only focus on local circuitry, we introduced the in vitro central nervous system (CNS) from neonatal rodents to simultaneously record a stable respiratory rhythm from both cervical and lumbar ventral roots (VRs).Electrical pulses supplied to multiple sites of brainstem evoked distinct VR responses with staggered onset in the rostro-caudal direction. Stimulation of ventrolateral medulla (VLM) resulted in higher events from homolateral VRs. Stimulating a lumbar dorsal root (DR) elicited responses even from cervical VRs, albeit small and delayed, confirming functional ascending pathways. Oximetric assessments detected optimal oxygen levels on brainstem and cortical surfaces, and histological analysis of internal brain structures indicated preserved neuron viability without astrogliosis. Serial ablations showed precollicular decerebration reducing respiratory burst duration and frequency and diminishing the area of lumbar DR and VR potentials elicited by DR stimulation, while pontobulbar transection increased the frequency and duration of respiratory bursts. Keeping legs attached allows for expressing a respiratory rhythm during hindlimb stimulation. Trains of pulses evoked episodes of fictive locomotion (FL) when delivered to VLM or to a DR, the latter with a slightly better FL than in isolated cords.In summary, suprapontine centers regulate spontaneous respiratory rhythms, as well as electrically evoked reflexes and spinal network activity. The current approach contributes to clarifying modulatory brain influences on the brainstem and spinal microcircuits during development. Novel preparation of the entire isolated CNS from newborn rats unveils suprapontine modulation on brainstem and spinal networks. Preparation views (A) with and without legs attached (B). Successful fictive respiration occurs with fast dissection from P0-P2 rats (C). Decerebration speeds up respiratory rhythm (D) and reduces spinal reflexes derived from both ventral and dorsal lumbar roots (E).
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Affiliation(s)
- Atiyeh Mohammadshirazi
- Neuroscience Department, International School for Advanced Studies (SISSA), Via Bonomea 265, 34136, Trieste, Italy.,Applied Neurophysiology and Neuropharmacology Lab, Istituto di Medicina Fisica e Riabilitazione (IMFR), Via Gervasutta 48, Udine, UD, Italy
| | - Rosamaria Apicella
- Neuroscience Department, International School for Advanced Studies (SISSA), Via Bonomea 265, 34136, Trieste, Italy.,Applied Neurophysiology and Neuropharmacology Lab, Istituto di Medicina Fisica e Riabilitazione (IMFR), Via Gervasutta 48, Udine, UD, Italy
| | - Benjamín A Zylberberg
- Instituto de Investigaciones en Medicina Traslacional (IIMT)-CONICET - Universidad Austral, Av. Pte. Perón 1500, Pilar, Buenos Aires, Argentina
| | - Graciela L Mazzone
- Instituto de Investigaciones en Medicina Traslacional (IIMT)-CONICET - Universidad Austral, Av. Pte. Perón 1500, Pilar, Buenos Aires, Argentina
| | - Giuliano Taccola
- Neuroscience Department, International School for Advanced Studies (SISSA), Via Bonomea 265, 34136, Trieste, Italy. .,Applied Neurophysiology and Neuropharmacology Lab, Istituto di Medicina Fisica e Riabilitazione (IMFR), Via Gervasutta 48, Udine, UD, Italy.
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Acute neuromodulation restores spinally-induced motor responses after severe spinal cord injury. Exp Neurol 2020; 327:113246. [DOI: 10.1016/j.expneurol.2020.113246] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 01/15/2020] [Accepted: 02/10/2020] [Indexed: 12/29/2022]
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3
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Coslovich T, Della Mora A, D'Angelo G, Ortolani F, Taccola G. Histamine H 3 Receptors Expressed in Ventral Horns Modulate Spinal Motor Output. Cell Mol Neurobiol 2020; 41:185-190. [PMID: 32211996 DOI: 10.1007/s10571-020-00831-4] [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: 12/02/2019] [Accepted: 03/16/2020] [Indexed: 11/29/2022]
Abstract
Motoneuron activity is modulated by histamine receptors. While H1 and H2 receptors have been widely explored, H3 histamine receptors (H3Rs) have not been sufficiently characterized. This paper targets the effects of the selective activation of H3Rs and their expression on the membranes of large ventral horn cells. The application of selective pharmacological agents to spinal cords isolated from neonatal rats was used to identify the presence of functional H3Rs on the membrane of physiologically identified lumbar motoneurons. Intra and extracellular recordings revealed that H3R agonist, α-methylhistamine, depolarized both single motoneurons and ventral roots, even in the presence of tetrodotoxin, an effect prevented by H3R antagonist, thioperamide. Finally, immunohistochemistry located the expression of H3Rs on a subpopulation of large cells in lamina IX. This study identifies H3Rs as a new exploitable pharmacological target against motor disturbances.
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Affiliation(s)
- Tamara Coslovich
- Neuroscience Department, International School for Advanced Studies (SISSA), via Bonomea 265, 34136, Trieste, TS, Italy.,SPINAL (Spinal Person Injury Neurorehabilitation Applied Laboratory), Istituto di Medicina Fisica e Riabilitazione (IMFR), via Gervasutta 48, Udine, UD, Italy
| | - Alberto Della Mora
- Department of Experimental Clinical Medicine, University of Udine, Piazzale Kolbe 3, Udine, Italy
| | - Giuseppe D'Angelo
- Neuroscience Department, International School for Advanced Studies (SISSA), via Bonomea 265, 34136, Trieste, TS, Italy.,SPINAL (Spinal Person Injury Neurorehabilitation Applied Laboratory), Istituto di Medicina Fisica e Riabilitazione (IMFR), via Gervasutta 48, Udine, UD, Italy
| | - Fulvia Ortolani
- Department of Experimental Clinical Medicine, University of Udine, Piazzale Kolbe 3, Udine, Italy
| | - Giuliano Taccola
- Neuroscience Department, International School for Advanced Studies (SISSA), via Bonomea 265, 34136, Trieste, TS, Italy. .,SPINAL (Spinal Person Injury Neurorehabilitation Applied Laboratory), Istituto di Medicina Fisica e Riabilitazione (IMFR), via Gervasutta 48, Udine, UD, Italy.
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Taccola G, Gad P, Culaclii S, Ichiyama RM, Liu W, Edgerton VR. Using EMG to deliver lumbar dynamic electrical stimulation to facilitate cortico-spinal excitability. Brain Stimul 2019; 13:20-34. [PMID: 31585723 DOI: 10.1016/j.brs.2019.09.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 08/06/2019] [Accepted: 09/24/2019] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Potentiation of synaptic activity in spinal networks is reflected in the magnitude of modulation of motor responses evoked by spinal and cortical input. After spinal cord injury, motor evoked responses can be facilitated by pairing cortical and peripheral nerve stimuli. OBJECTIVE To facilitate synaptic potentiation of cortico-spinal input with epidural electrical stimulation, we designed a novel neuromodulation method called dynamic stimulation (DS), using patterns derived from hind limb EMG signal during stepping. METHODS DS was applied dorsally to the lumbar enlargement through a high-density epidural array composed of independent platinum-based micro-electrodes. RESULTS In fully anesthetized intact adult rats, at the interface array/spinal cord, the temporal and spatial features of DS neuromodulation affected the entire lumbosacral network, particularly the most rostral and caudal segments covered by the array. DS induced a transient (at least 1 min) increase in spinal cord excitability and, compared to tonic stimulation, generated a more robust potentiation of the motor output evoked by single pulses applied to the spinal cord. When sub-threshold pulses were selectively applied to a cortical motor area, EMG responses from the contralateral leg were facilitated by the delivery of DS to the lumbosacral cord. Finally, based on motor-evoked responses, DS was linked to a greater amplitude of motor output shortly after a calibrated spinal cord contusion. CONCLUSION Compared to traditional tonic waveforms, DS amplifies both spinal and cortico-spinal input aimed at spinal networks, thus significantly increasing the potential and accelerating the rate of functional recovery after a severe spinal lesion.
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Affiliation(s)
- Giuliano Taccola
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA, 90095, USA; Neuroscience Department, International School for Advanced Studies (SISSA), Bonomea 265, Trieste, Italy; School of Biomedical Sciences, University of Leeds, Leeds, LS2 9JT, UK.
| | - Parag Gad
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA, 90095, USA
| | - Stanislav Culaclii
- Department of Bioengineering, University of California, Los Angeles, CA, 90095, USA
| | | | - Wentai Liu
- Department of Bioengineering, University of California, Los Angeles, CA, 90095, USA; Brain Research Institute, University of California, Los Angeles, CA, 90095, USA
| | - V Reggie Edgerton
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA, 90095, USA; Department of Neurobiology, University of California, Los Angeles, CA, 90095, USA; Department of Neurosurgery, University of California, Los Angeles, CA, 90095, USA; Brain Research Institute, University of California, Los Angeles, CA, 90095, USA; The Centre for Neuroscience and Regenerative Medicine, Faculty of Science, University of Technology Sydney, Ultimo, 2007, NSW, Australia; Institut Guttmann, Hospital de Neurorehabilitació, Institut Universitari Adscrit a La Universitat Autònoma de Barcelona, Barcelona, 08916, Badalona, Spain.
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Spinal Cord Epidural Stimulation for Lower Limb Motor Function Recovery in Individuals with Motor Complete Spinal Cord Injury. Phys Med Rehabil Clin N Am 2019; 30:337-354. [DOI: 10.1016/j.pmr.2018.12.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Dingu N, Deumens R, Taccola G. Afferent Input Induced by Rhythmic Limb Movement Modulates Spinal Neuronal Circuits in an Innovative Robotic In Vitro Preparation. Neuroscience 2018; 394:44-59. [PMID: 30342198 DOI: 10.1016/j.neuroscience.2018.10.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 10/08/2018] [Accepted: 10/09/2018] [Indexed: 12/30/2022]
Abstract
Locomotor patterns are mainly modulated by afferent feedback, but its actual contribution to spinal network activity during continuous passive limb training is still unexplored. To unveil this issue, we devised a robotic in vitro setup (Bipedal Induced Kinetic Exercise, BIKE) to induce passive pedaling, while simultaneously recording low-noise ventral and dorsal root (VR and DR) potentials in isolated neonatal rat spinal cords with hindlimbs attached. As a result, BIKE evoked rhythmic afferent volleys from DRs, reminiscent of pedaling speed. During BIKE, spontaneous VR activity remained unchanged, while a DR rhythmic component paired the pedaling pace. Moreover, BIKE onset rarely elicited brief episodes of fictive locomotion (FL) and, when trains of electrical pulses were simultaneously applied to a DR, it increased the amplitude, but not the number, of FL cycles. When BIKE was switched off after a 30-min training, the number of electrically induced FL oscillations was transitorily facilitated, without affecting VR reflexes or DR potentials. However, 90 min of BIKE no longer facilitated FL, but strongly depressed area of VR reflexes and stably increased antidromic DR discharges. Patch clamp recordings from single motoneurons after 90-min sessions indicated an increased frequency of both fast- and slow-decaying synaptic input to motoneurons. In conclusion, hindlimb rhythmic and alternated pedaling for different durations affects distinct dorsal and ventral spinal networks by modulating excitatory and inhibitory input to motoneurons. These results suggest defining new parameters for effective neurorehabilitation that better exploits spinal circuit activity.
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Affiliation(s)
- Nejada Dingu
- Neuroscience Department, International School for Advanced Studies (SISSA), via Bonomea 265, Trieste, TS, Italy; SPINAL (Spinal Person Injury Neurorehabilitation Applied Laboratory), Istituto di Medicina Fisica e Riabilitazione (IMFR), via Gervasutta 48, Udine, UD, Italy
| | - Ronald Deumens
- Institute of Neuroscience, Université catholique de Louvain, Av. Hippocrate 54, Brussels, Belgium
| | - Giuliano Taccola
- Neuroscience Department, International School for Advanced Studies (SISSA), via Bonomea 265, Trieste, TS, Italy; SPINAL (Spinal Person Injury Neurorehabilitation Applied Laboratory), Istituto di Medicina Fisica e Riabilitazione (IMFR), via Gervasutta 48, Udine, UD, Italy.
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Harkema SJ, Rejc E, Angeli CA. Neuromodulation of the Spinal Cord for Movement Restoration. Neuromodulation 2018. [DOI: 10.1016/b978-0-12-805353-9.00098-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Taccola G, Sayenko D, Gad P, Gerasimenko Y, Edgerton VR. And yet it moves: Recovery of volitional control after spinal cord injury. Prog Neurobiol 2017; 160:64-81. [PMID: 29102670 PMCID: PMC5773077 DOI: 10.1016/j.pneurobio.2017.10.004] [Citation(s) in RCA: 114] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 10/09/2017] [Accepted: 10/21/2017] [Indexed: 12/12/2022]
Abstract
Preclinical and clinical neurophysiological and neurorehabilitation research has generated rather surprising levels of recovery of volitional sensory-motor function in persons with chronic motor paralysis following a spinal cord injury. The key factor in this recovery is largely activity-dependent plasticity of spinal and supraspinal networks. This key factor can be triggered by neuromodulation of these networks with electrical and pharmacological interventions. This review addresses some of the systems-level physiological mechanisms that might explain the effects of electrical modulation and how repetitive training facilitates the recovery of volitional motor control. In particular, we substantiate the hypotheses that: (1) in the majority of spinal lesions, a critical number and type of neurons in the region of the injury survive, but cannot conduct action potentials, and thus are electrically non-responsive; (2) these neuronal networks within the lesioned area can be neuromodulated to a transformed state of electrical competency; (3) these two factors enable the potential for extensive activity-dependent reorganization of neuronal networks in the spinal cord and brain, and (4) propriospinal networks play a critical role in driving this activity-dependent reorganization after injury. Real-time proprioceptive input to spinal networks provides the template for reorganization of spinal networks that play a leading role in the level of coordination of motor pools required to perform a given functional task. Repetitive exposure of multi-segmental sensory-motor networks to the dynamics of task-specific sensory input as occurs with repetitive training can functionally reshape spinal and supraspinal connectivity thus re-enabling one to perform complex motor tasks, even years post injury.
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Affiliation(s)
- G Taccola
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA; Neuroscience Department, International School for Advanced Studies (SISSA), Bonomea 265, Trieste, Italy
| | - D Sayenko
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA
| | - P Gad
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA
| | - Y Gerasimenko
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA; Pavlov Institute of Physiology, St. Petersburg 199034, Russia
| | - V R Edgerton
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA; Department of Neurobiology, University of California, Los Angeles, CA 90095 USA; Department of Neurosurgery, University of California, Los Angeles, CA 90095 USA; Brain Research Institute, University of California, Los Angeles, CA 90095 USA; The Centre for Neuroscience and Regenerative Medicine, Faculty of Science, University of Technology Sydney, Ultimo, 2007 NSW, Australia; Institut Guttmann, Hospital de Neurorehabilitació, Institut Universitari adscrit a la Universitat Autònoma de Barcelona, Barcelona, 08916 Badalona, Spain.
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Illis LS. Spinal cord stimulation. Spinal Cord 2017; 55:624. [DOI: 10.1038/sc.2016.81] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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10
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Shah PK, Lavrov I. Spinal Epidural Stimulation Strategies: Clinical Implications of Locomotor Studies in Spinal Rats. Neuroscientist 2017; 23:664-680. [PMID: 28345483 DOI: 10.1177/1073858417699554] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Significant advancements in spinal epidural stimulation (ES) strategies to enable volitional motor control in persons with a complete spinal cord injury (SCI) have generated much excitement in the field of neurorehabilitation. Still, an obvious gap lies in the ability of ES to effectively generate a robust locomotor stepping response after a complete SCI in rodents, but not in humans. In order to reveal potential discrepancies between rodent and human studies that account for this void, in this review, we summarize the findings of studies that have utilized ES strategies to enable successful hindlimb stepping in spinal rats. Recent clinical and preclinical evidence indicates that motor training with ES plays a crucial role in tuning spinal neural circuitry to generate meaningful motor output. Concurrently administered pharmacology can also facilitate the circuitry to provide near optimal motor performance in SCI rats. However, as of today, the evidence for pharmacological agents to enhance motor function in persons with complete SCI is insignificant. These and other recent findings discussed in this review provide insight into addressing the translational gap, guide the design of relevant preclinical experiments, and facilitate development of new approaches for motor recovery in patients with complete SCIs.
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Affiliation(s)
- Prithvi K Shah
- 1 Division of Rehabilitation Sciences, School of Health Technology and Management, Stony Brook University, Stony Brook, NY, USA.,2 Department of Neurobiology, Stony Brook University, Stony Brook, NY, USA
| | - Igor Lavrov
- 3 Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA.,4 Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA.,5 Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
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Correction: Multi-site spinal stimulation strategies to enhance locomotion after paralysis. Neural Regen Res 2017; 12:161-162. [PMID: 28250764 PMCID: PMC5319224 DOI: 10.4103/1673-5374.199010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Shaping the Output of Lumbar Flexor Motoneurons by Sacral Neuronal Networks. J Neurosci 2016; 37:1294-1311. [PMID: 28025254 DOI: 10.1523/jneurosci.2213-16.2016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 12/11/2016] [Accepted: 12/14/2016] [Indexed: 12/27/2022] Open
Abstract
The ability to improve motor function in spinal cord injury patients by reactivating spinal central pattern generators (CPGs) requires the elucidation of neurons and pathways involved in activation and modulation of spinal networks in accessible experimental models. Previously we reported on adrenoceptor-dependent sacral control of lumbar flexor motoneuron firing in newborn rats. The current work focuses on clarification of the circuitry and connectivity involved in this unique modulation and its potential use. Using surgical manipulations of the spinal gray and white matter, electrophysiological recordings, and confocal microscopy mapping, we found that methoxamine (METH) activation of sacral networks within the ventral aspect of S2 segments was sufficient to produce alternating rhythmic bursting (0.15-1 Hz) in lumbar flexor motoneurons. This lumbar rhythm depended on continuity of the ventral funiculus (VF) along the S2-L2 segments. Interrupting the VF abolished the rhythm and replaced it by slow unstable bursting. Calcium imaging of S1-S2 neurons, back-labeled via the VF, revealed that ∼40% responded to METH, mostly by rhythmic firing. All uncrossed projecting METH responders and ∼70% of crossed projecting METH responders fired with the concurrent ipsilateral motor output, while the rest (∼30%) fired with the contralateral motor output. We suggest that METH-activated sacral CPGs excite ventral clusters of sacral VF neurons to deliver the ascending drive required for direct rhythmic activation of lumbar flexor motoneurons. The capacity of noradrenergic-activated sacral CPGs to modulate the activity of lumbar networks via sacral VF neurons provides a novel way to recruit rostral lumbar motoneurons and modulate the output required to execute various motor behaviors. SIGNIFICANCE STATEMENT Spinal central pattern generators (CPGs) produce the rhythmic output required for coordinating stepping and stabilizing the body axis during movements. Electrical stimulation and exogenous drugs can reactivate the spinal CPGs and improve the motor function in the absence of descending supraspinal control. Since the body-stabilizing sacral networks can activate and modulate the limb-moving lumbar circuitry, it is important to clarify the functional organization of sacral and lumbar networks and their linking pathways. Here we decipher the ascending circuitry linking adrenoceptor-activated sacral CPGs and lumbar flexor motoneurons, thereby providing novel insights into mechanisms by which sacral circuitry recruits lumbar flexors, and enhances the motor output during lumbar afferent-induced locomotor rhythms. Moreover, our findings might help to improve drug/electrical stimulation-based therapy to accelerate locomotor-based rehabilitation.
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Interactions between Dorsal and Ventral Root Stimulation on the Generation of Locomotor-Like Activity in the Neonatal Mouse Spinal Cord. eNeuro 2016; 3:eN-NWR-0101-16. [PMID: 27419215 PMCID: PMC4937207 DOI: 10.1523/eneuro.0101-16.2016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 05/24/2016] [Accepted: 05/31/2016] [Indexed: 12/23/2022] Open
Abstract
We investigated whether dorsal (DR) and ventral root (VR) stimulus trains engage common postsynaptic components to activate the central pattern generator (CPG) for locomotion in the neonatal mouse spinal cord. VR stimulation did not activate the first order interneurons mediating the activation of the locomotor CPG by sacrocaudal afferent stimulation. Simultaneous stimulation of adjacent dorsal or ventral root pairs, subthreshold for evoking locomotor-like activity, did not summate to activate the CPG. This suggests that locomotor-like activity is triggered when a critical class of efferent or afferent axons is stimulated and does not depend on the number of stimulated axons or activated postsynaptic neurons. DR- and VR-evoked episodes exhibited differences in the coupling between VR pairs. In DR-evoked episodes, the coupling between the ipsilateral and contralateral flexor/extensor roots was similar and stronger than the bilateral extensor roots. In VR-evoked episodes, ipsilateral flexor/extensor coupling was stronger than both the contralateral flexor/extensor and the bilateral extensor coupling. For both types of stimulation, the coupling was greatest between the bilateral L1/L2 flexor-dominated roots. This indicates that the recruitment and/or the firing pattern of motoneurons differed in DR and VR-evoked episodes. However, the DR and VR trains do not appear to activate distinct CPGs because trains of DR and VR stimuli at frequencies too low to evoke locomotor-like activity did so when they were interleaved. These results indicate that the excitatory actions of VR stimulation converge onto the CPG through an unknown pathway that is not captured by current models of the locomotor CPG.
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Dose F, Taccola G. Two Distinct Stimulus Frequencies Delivered Simultaneously at Low Intensity Generate Robust Locomotor Patterns. Neuromodulation 2016; 19:563-75. [PMID: 26968869 DOI: 10.1111/ner.12402] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 12/21/2015] [Accepted: 12/29/2015] [Indexed: 12/25/2022]
Abstract
OBJECTIVES Explore the primary characteristics of afferent noisy stimuli, which optimally activate locomotor patterns at low intensity. MATERIALS AND METHODS Intracellular and extracellular electrophysiological traces were derived from single motoneurons and from ventral roots, respectively. From these recordings, we obtained noisy stimulating protocols, delivered to a dorsal root (DR) of an isolated neonatal rat spinal cord, while recording fictive locomotion (FL) from ventral roots. RESULTS We decreased complexity of efficient noisy stimulating protocols down to single cell spikes. Then, we identified four main components within the power spectrum of these signals and used them to construct a basic multifrequency protocol of rectangular impulses, able to induce FL. Further disassembling generated the minimum stimulation paradigm that activated FL, which consisted of a pair of 35 and 172 Hz frequency pulse trains, strongly effective at low intensity when delivered either jointly to one lumbosacral DR or as single simultaneous trains to two distinct DRs. This simplified pulse schedule always activated a locomotor rhythm, even when delivered for a very short time (500 ms). One prerequisite for the two-frequency protocol to activate FL at low intensity when applied to sacrocaudal afferents was the ability to induce ascending volleys of greater amplitude. CONCLUSION Multifrequency protocols can support future studies in defining the most effective characteristics for electrical stimulation to reactivate stepping following motor injury.
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Affiliation(s)
- Francesco Dose
- Neuroscience Area, International School for Advanced Studies (SISSA), Trieste, TS, Italy.,SPINAL (Spinal Person Injury Neurorehabilitation Applied Laboratory), Istituto di Medicina Fisica e Riabilitazione (IMFR), Udine, UD, Italy
| | - Giuliano Taccola
- Neuroscience Area, International School for Advanced Studies (SISSA), Trieste, TS, Italy.,SPINAL (Spinal Person Injury Neurorehabilitation Applied Laboratory), Istituto di Medicina Fisica e Riabilitazione (IMFR), Udine, UD, Italy
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Shah PK, Gerasimenko Y. Multi-site spinal stimulation strategies to enhance locomotion after paralysis. Neural Regen Res 2016; 11:1926-1927. [PMID: 28197186 PMCID: PMC5270428 DOI: 10.4103/1673-5374.197131] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Prithvi K Shah
- Division of Rehabilitation Sciences, School of Health Technology and Management, Stony Brook University, Stony Brook, NY, USA; Department of Neurobiology, Life Science Building, Stony Brook University, Stony Brook, NY, USA
| | - Yury Gerasimenko
- Department of Integrative Biology and Physiology, Charles E Young Dr, University of California, Los Angeles, CA, USA; Pavlov Institute of Physiology, St. Petersburg, Russia; Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
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Dingu N, Deumens R, Taccola G. Electrical Stimulation Able to Trigger Locomotor Spinal Circuits Also Induces Dorsal Horn Activity. Neuromodulation 2015; 19:38-46. [DOI: 10.1111/ner.12354] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 07/29/2015] [Accepted: 09/01/2015] [Indexed: 12/22/2022]
Affiliation(s)
- Nejada Dingu
- Neuroscience Department; International School for Advanced Studies (SISSA); Trieste Italy
- SPINAL (Spinal Person Injury Neurorehabilitation Applied Laboratory); Istituto di Medicina Fisica e Riabilitazione (IMFR); Udine Italy
| | - Ronald Deumens
- Institute of Neuroscience; Université catholique de Louvain (UCL); Brussels Belgium
| | - Giuliano Taccola
- Neuroscience Department; International School for Advanced Studies (SISSA); Trieste Italy
- SPINAL (Spinal Person Injury Neurorehabilitation Applied Laboratory); Istituto di Medicina Fisica e Riabilitazione (IMFR); Udine Italy
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