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Nascimento F, Özyurt MG, Halablab K, Bhumbra GS, Caron G, Bączyk M, Zytnicki D, Manuel M, Roselli F, Brownstone R, Beato M. Spinal microcircuits go through multiphasic homeostatic compensations in a mouse model of motoneuron degeneration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.10.588918. [PMID: 38645210 PMCID: PMC11030447 DOI: 10.1101/2024.04.10.588918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
In neurological conditions affecting the brain, early-stage neural circuit adaption is key for long-term preservation of normal behaviour. We tested if motoneurons and respective microcircuits also adapt in the initial stages of disease progression in a mouse model of progressive motoneuron degeneration. Using a combination of in vitro and in vivo electrophysiology and super-resolution microscopy, we found that, preceding muscle denervation and motoneuron death, recurrent inhibition mediated by Renshaw cells is reduced in half due to impaired quantal size associated with decreased glycine receptor density. Additionally, higher probability of release from proprioceptive Ia terminals leads to increased monosynaptic excitation to motoneurons. Surprisingly, the initial impairment in recurrent inhibition is not a widespread feature of inhibitory spinal circuits, such as group I inhibitory afferents, and is compensated at later stages of disease progression. We reveal that in disease conditions, spinal microcircuits undergo specific multiphasic homeostatic compensations to preserve force output.
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Affiliation(s)
- Filipe Nascimento
- Department of Neuroscience Physiology and Pharmacology (NPP), Gower Street, University College London, WC1E 6BT, UK
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - M. Görkem Özyurt
- Department of Neuroscience Physiology and Pharmacology (NPP), Gower Street, University College London, WC1E 6BT, UK
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Kareen Halablab
- Department of Neurology, Ulm University, Ulm, Germany
- German Centre for Neurodegenerative Diseases-Ulm (DZNE-Ulm), Ulm, Germany
| | - Gardave Singh Bhumbra
- Department of Neuroscience Physiology and Pharmacology (NPP), Gower Street, University College London, WC1E 6BT, UK
| | - Guillaume Caron
- Saints-Pères Paris Institute for the Neurosciences (SPPIN), Université Paris Cité, Centre National de la Recherche Scientifique (CNRS), Paris, France
| | - Marcin Bączyk
- Department of Neurobiology, Poznań University of Physical Education, Poznań, Poland
| | - Daniel Zytnicki
- Saints-Pères Paris Institute for the Neurosciences (SPPIN), Université Paris Cité, Centre National de la Recherche Scientifique (CNRS), Paris, France
| | - Marin Manuel
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, USA
- George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI, USA
| | - Francesco Roselli
- Department of Neurology, Ulm University, Ulm, Germany
- German Centre for Neurodegenerative Diseases-Ulm (DZNE-Ulm), Ulm, Germany
| | - Rob Brownstone
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Marco Beato
- Department of Neuroscience Physiology and Pharmacology (NPP), Gower Street, University College London, WC1E 6BT, UK
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Alvarado-Navarrete MDC, Pliego-Carrillo AC, Ledesma-Ramírez CI, Cuellar CA. Post-activation depression of the Hoffman reflex is not altered by galvanic vestibular stimulation in healthy subjects. Front Integr Neurosci 2023; 17:1234613. [PMID: 37711909 PMCID: PMC10499171 DOI: 10.3389/fnint.2023.1234613] [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: 06/05/2023] [Accepted: 08/08/2023] [Indexed: 09/16/2023] Open
Abstract
The comprehension of the neural elements interacting in the spinal cord affected by vestibular input will contribute to the understanding of movement execution in normal and pathological conditions. In this context, Hoffman's reflex (H-reflex) has been used to evaluate transient excitability changes on the spinal cord descending pathways. The post-activation depression (P-AD) of the H-reflex consists of evoking consecutive responses (>1 Hz) provoking an amplitude depression, which has been shown to diminish in pathological conditions (i.e., spasticity, diabetic neuropathy). Galvanic Vestibular Stimulation (GVS) is a non-invasive method that activates the vestibular afferents and has been used to study the excitability of the H-reflex applied as a conditioning pulse. To our knowledge, there are no reports evaluating the P-AD during and after GVS. Our primary aim was to determine if GVS alters the P-AD evoked by stimulating the tibial nerve at 0.1, 1, 5, and 10 Hz, recording in the gastrocnemius and soleus muscles. Direct current stimulation of 2.0 ± 0.6 mA with the cathode ipsilateral (Ipsi) or contralateral (Contra) to the H-reflex electrode montage was applied bilaterally over the mastoid process in 19 healthy subjects. The P-AD's immediate post-GVS response (P Ipsi, P Contra) was also analyzed. Secondarily, we analyzed the excitability of the H-reflex during GVS. Responses evoked at 0.1 Hz with GVS, post-GVS, and a Control (no GVS) condition were used for comparisons. Our results show that P-AD persisted in all subjects despite increased excitability induced by GVS: statistical significance was found when comparing P-AD at 1, 5, and 10 Hz with the corresponding condition (Control, Ipsi, P Ipsi, Contra, P Contra) at 0.1 Hz (p < 0.001). Additionally, the increase in excitability produced by GVS was quantified for the first H-reflex of each P-AD stimulation frequency. The percentage change for all GVS conditions surpassed the Control by at least 20%, being statistically significant for Contra compared to Control (p < 0.01). In summary, although GVS increases the excitability of the vestibulospinal pathway at a premotor level, the neural inhibitory mechanism present in P-AD remains unaltered in healthy subjects.
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Affiliation(s)
| | - Adriana C. Pliego-Carrillo
- Biomedical Engineering, School of Medicine, Autonomous University of the State of Mexico, Toluca, Mexico
| | | | - Carlos A. Cuellar
- School of Sport Sciences, Universidad Anáhuac México, Huixquilucan, Mexico
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Saito A, Mizuno T. Effects of patterned electrical sensory nerve stimulation and static stretching on joint range of motion and passive torque. Front Neurosci 2023; 17:1205602. [PMID: 37674515 PMCID: PMC10478221 DOI: 10.3389/fnins.2023.1205602] [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: 05/17/2023] [Accepted: 07/28/2023] [Indexed: 09/08/2023] Open
Abstract
Static stretching and proprioceptive neuromuscular facilitation stretching techniques can modulate specific neural mechanisms to improve the range of motion. However, the effects of modulation of these neural pathways on changes in the range of motion with static stretching remain unclear. Patterned electrical stimulation of the sensory nerve induces plastic changes in reciprocal Ia inhibition. The present study examined the effects of patterned electrical stimulation and static stretching on a range of motion and passive torque in plantarflexion muscles. The subjects were 14 young men (age 20.8 ± 1.3 years). The effects of patterned electrical stimulation (10 pulses at 100 Hz every 1.5 s) or uniform electrical stimulation (one pulse every 150 ms) to the common peroneal nerve for 20 min on reciprocal Ia inhibition of the Hoffman reflex (H-reflex) were examined. Reciprocal Ia inhibition was evaluated as short-latency suppression of the soleus H-reflex by conditioning stimulation of the common peroneal nerve. Then, the effects of transcutaneous electrical nerve stimulation (patterned electrical stimulation or uniform electrical stimulation) or prolonged resting (without electrical stimulation) and static 3-min stretching on the maximal dorsiflexion angle and passive torque were investigated. The passive ankle dorsiflexion test was performed on an isokinetic dynamometer. Stretch tolerance and stiffness of the muscle-tendon unit were evaluated by the peak and slope of passive torques, respectively. Patterned electrical stimulation significantly increased reciprocal Ia inhibition of soleus H-reflex amplitude (9.7 ± 6.1%), but uniform electrical stimulation decreased it significantly (19.5 ± 8.8%). The maximal dorsiflexion angle was significantly changed by patterned electrical stimulation (4.0 ± 1.4°), uniform electrical stimulation (3.8 ± 2.3°), and stretching without electrical stimulation (2.1 ± 3.3°). The increase in stretch tolerance was significantly greater after patterned electrical stimulation and uniform electrical stimulation than after stretching without electrical stimulation. Stiffness of the muscle-tendon unit was significantly decreased by patterned electrical stimulation, uniform electrical stimulation, and stretching without electrical stimulation. Transcutaneous electrical nerve stimulation and static stretching improve stretch tolerance regardless of the degree of reciprocal Ia inhibition.
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Affiliation(s)
- Akira Saito
- Center for Health and Science, Kyushu Sangyo University, Fukuoka, Japan
| | - Takamasa Mizuno
- Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya, Japan
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Xenofondos A, Papavasileiou A, Bassa E, Vrabas IS, Patikas DA. Postactivation Potentiation and the Asynchronous Action of Muscular and Neural Responses. Int J Sports Physiol Perform 2023:1-9. [PMID: 37295786 DOI: 10.1123/ijspp.2022-0336] [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: 09/02/2022] [Revised: 03/22/2023] [Accepted: 05/02/2023] [Indexed: 06/12/2023]
Abstract
PURPOSE This study examined the underlying mechanisms of postactivation potentiation and the time course of muscular- and neural-related variables. METHODS Fourteen trained males executed 4 sets of six 6-second maximum isometric conditioning plantar flexions, with 15 seconds and 2 minutes of interval between the contractions and sets, respectively. Peak twitch torque (TT), rate of torque development, time to peak torque, half relaxation time, and the neural-related variables of H-reflex and electromyogram, normalized to the maximum M-wave (H/M and RMS/M, respectively), were evaluated, as well as the level of the voluntary activation, assessed by the twitch interpolation technique. All neural-related variables were analyzed for the trial within each set when TT was maximal and for the trial within each set when the neural-related variable itself was maximal. RESULTS Compared with the baseline measures, TT and rate of torque development significantly increased in all sets (P < .001), whereas time to peak torque and half relaxation time significantly decreased in sets 1 to 4 and 2 to 4, respectively (P < .001). However, H/M and the RMS/M did not change for the repetition of each set for which the TT was maximal (P > .05). Interestingly, the within-set maximum H/M ratio of the lateral gastrocnemius muscle revealed a significant increase in all sets (P < .05), compared with the baseline measures. CONCLUSION One set of 4 contractions with 6-second duration is sufficient to cause postactivation potentiation for most participants, whereas peak TT augmentation does not coincide with changes in the examined neural-related variables. Further experiments should consider the time lag on their maximal values and their inherent between-participants variability.
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Affiliation(s)
- Anthi Xenofondos
- Physical Education and Sport Sciences, Frederick University, Nicosia,Cyprus
- Faculty of Physical Education and Sport Sciences, Aristotle University of Thessaloniki, Thessaloniki,Greece
| | - Anastasia Papavasileiou
- Faculty of Physical Education and Sport Sciences, Aristotle University of Thessaloniki, Thessaloniki,Greece
| | - Eleni Bassa
- Faculty of Physical Education and Sport Sciences, Aristotle University of Thessaloniki, Thessaloniki,Greece
| | - Ioannis S Vrabas
- Faculty of Physical Education and Sport Sciences, Aristotle University of Thessaloniki, Thessaloniki,Greece
| | - Dimitrios A Patikas
- Faculty of Physical Education and Sport Sciences, Aristotle University of Thessaloniki, Thessaloniki,Greece
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Nevanperä S, Hu N, Walker S, Avela J, Piirainen JM. Modulation of H-reflex and V-wave responses during dynamic balance perturbations. Exp Brain Res 2023; 241:1599-1610. [PMID: 37142781 DOI: 10.1007/s00221-023-06625-6] [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: 10/04/2022] [Accepted: 04/25/2023] [Indexed: 05/06/2023]
Abstract
Motoneuron excitability is possible to measure using H-reflex and V-wave responses. However, it is not known how the motor control is organized, how the H-reflex and V-wave responses modulate and how repeatable these are during dynamic balance perturbations. To assess the repeatability, 16 participants (8 men, 8 women) went through two, identical measurement sessions with ~ 48 h intervals, where maximal isometric plantar flexion (IMVC) and dynamic balance perturbations in horizontal, anterior-posterior direction were performed. Soleus muscle (SOL) neural modulation during balance perturbations were measured at 40, 70, 100 and 130 ms after ankle movement by using both H-reflex and V-wave methods. V-wave, which depicts the magnitude of efferent motoneuronal output (Bergmann et al. in JAMA 8:e77705, 2013), was significantly enhanced as early as 70 ms after the ankle movement. Both the ratio of M-wave-normalized V-wave (0.022-0.076, p < 0.001) and H-reflex (0.386-0.523, p < 0.001) increased significantly at the latency of 70 ms compared to the latency of 40 ms and remained at these levels at latter latencies. In addition, M-wave normalized V-wave/H-reflex ratio increased from 0.056 to 0.179 (p < 0.001). The repeatability of V-wave demonstrated moderate-to-substantial repeatability (ICC = 0.774-0.912) whereas the H-reflex was more variable showing fair-to-substantial repeatability (ICC = 0.581-0.855). As a conclusion, V-wave was enhanced already at 70 ms after the perturbation, which may indicate that increased activation of motoneurons occurred due to changes in descending drive. Since this is a short time-period for voluntary activity, some other, potentially subcortical responses might be involved for V-wave increment rather than voluntary drive. Our results addressed the usability and repeatability of V-wave method during dynamic conditions, which can be utilized in future studies.
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Affiliation(s)
- Samuli Nevanperä
- Sports Technology Program, Faculty of Sport and Health Sciences, University of Jyväskylä, Kidekuja 2, 88610, Vuokatti, Finland.
- NeuroMuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Rautpohjankatu 8, PL35, 40700, Jyväskylä, Finland.
| | - Nijia Hu
- NeuroMuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Rautpohjankatu 8, PL35, 40700, Jyväskylä, Finland
| | - Simon Walker
- NeuroMuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Rautpohjankatu 8, PL35, 40700, Jyväskylä, Finland
| | - Janne Avela
- NeuroMuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Rautpohjankatu 8, PL35, 40700, Jyväskylä, Finland
| | - Jarmo M Piirainen
- Sports Technology Program, Faculty of Sport and Health Sciences, University of Jyväskylä, Kidekuja 2, 88610, Vuokatti, Finland
- NeuroMuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Rautpohjankatu 8, PL35, 40700, Jyväskylä, Finland
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Skiadopoulos A, Famodimu GO, Solomon SK, Agarwal P, Harel NY, Knikou M. Priming locomotor training with transspinal stimulation in people with spinal cord injury: study protocol of a randomized clinical trial. Trials 2023; 24:145. [PMID: 36841773 PMCID: PMC9960224 DOI: 10.1186/s13063-023-07193-4] [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: 02/01/2023] [Accepted: 02/20/2023] [Indexed: 02/27/2023] Open
Abstract
BACKGROUND The seemingly simple tasks of standing and walking require continuous integration of complex spinal reflex circuits between descending motor commands and ascending sensory inputs. Spinal cord injury greatly impairs standing and walking ability, but both improve with locomotor training. However, even after multiple locomotor training sessions, abnormal muscle activity and coordination persist. Thus, locomotor training alone cannot fully optimize the neuronal plasticity required to strengthen the synapses connecting the brain, spinal cord, and local circuits and potentiate neuronal activity based on need. Transcutaneous spinal cord (transspinal) stimulation alters motoneuron excitability over multiple segments by bringing motoneurons closer to threshold, a prerequisite for effectively promoting spinal locomotor network neuromodulation and strengthening neural connectivity of the injured human spinal cord. Importantly, whether concurrent treatment with transspinal stimulation and locomotor training maximizes motor recovery after spinal cord injury is unknown. METHODS Forty-five individuals with chronic spinal cord injury are receiving 40 sessions of robotic gait training primed with 30 Hz transspinal stimulation at the Thoracic 10 vertebral level. Participants are randomized to receive 30 min of active or sham transspinal stimulation during standing or active transspinal stimulation while supine followed by 30 min of robotic gait training. Over the course of locomotor training, the body weight support, treadmill speed, and leg guidance force are adjusted as needed for each participant based on absence of knee buckling during the stance phase and toe dragging during the swing phase. At baseline and after completion of all therapeutic sessions, neurophysiological recordings registering corticospinal and spinal neural excitability changes along with clinical assessment measures of standing and walking, and autonomic function via questionnaires regarding bowel, bladder, and sexual function are taken. DISCUSSION The results of this mechanistic randomized clinical trial will demonstrate that tonic transspinal stimulation strengthens corticomotoneuronal connectivity and dynamic neuromodulation through posture-dependent corticospinal and spinal neuroplasticity. We anticipate that this mechanistic clinical trial will greatly impact clinical practice because, in real-world clinical settings, noninvasive transspinal stimulation can be more easily and widely implemented than invasive epidural stimulation. Additionally, by applying multiple interventions to accelerate motor recovery, we are employing a treatment regimen that reflects a true clinical approach. TRIAL REGISTRATION ClinicalTrials.gov NCT04807764 . Registered on March 19, 2021.
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Affiliation(s)
- Andreas Skiadopoulos
- grid.254498.60000 0001 2198 5185Klab4Recovery Research Program, The City University of New York, College of Staten Island, Staten Island, NY USA ,grid.254498.60000 0001 2198 5185Department of Physical Therapy, College of Staten Island, The City University of New York, Staten Island, NY USA
| | - Grace O. Famodimu
- Spinal Cord Damage Research Center, James J. Peters Department of Veterans Affairs Medical Center, Bronx, NY USA
| | - Shammah K. Solomon
- grid.254498.60000 0001 2198 5185Klab4Recovery Research Program, The City University of New York, College of Staten Island, Staten Island, NY USA ,grid.254498.60000 0001 2198 5185Department of Physical Therapy, College of Staten Island, The City University of New York, Staten Island, NY USA
| | - Parul Agarwal
- grid.59734.3c0000 0001 0670 2351Population Health Science & Policy, Institute for Health Care Delivery Science, Icahn School of Medicine at Mount Sinai, Manhattan, NY USA
| | - Noam Y. Harel
- Spinal Cord Damage Research Center, James J. Peters Department of Veterans Affairs Medical Center, Bronx, NY USA ,grid.59734.3c0000 0001 0670 2351Population Health Science & Policy, Institute for Health Care Delivery Science, Icahn School of Medicine at Mount Sinai, Manhattan, NY USA
| | - Maria Knikou
- Klab4Recovery Research Program, The City University of New York, College of Staten Island, Staten Island, NY, USA. .,Department of Physical Therapy, College of Staten Island, The City University of New York, Staten Island, NY, USA. .,PhD Program in Biology and Collaborative Neuroscience Program, Graduate Center of The City University of New York and College of Staten Island, Manhattan & Staten Island, NY, USA.
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Skiadopoulos A, Famodimu GO, Solomon SK, Agrawal P, Harel NY, Knikou M. Priming locomotor training with transspinal stimulation in people with spinal cord injury: study protocol of a randomized clinical trial. RESEARCH SQUARE 2023:rs.3.rs-2527617. [PMID: 36824823 PMCID: PMC9949167 DOI: 10.21203/rs.3.rs-2527617/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Background The seemingly simple tasks of standing and walking require continuous integration of complex spinal reflex circuits between descending motor commands and ascending sensory inputs. Spinal cord injury greatly impairs standing and walking ability, but both improve with locomotor training. However, even after multiple locomotor training sessions, abnormal muscle activity and coordination persist. Thus, locomotor training alone cannot fully optimize the neuronal plasticity required to strengthen the synapses connecting the brain, spinal cord, and local circuits and potentiate neuronal activity based on need. Transcutaneous spinal cord (transspinal) stimulation alters motoneuron excitability over multiple segments by bringing motoneurons closer to threshold, a prerequisite for effectively promoting spinal locomotor network neuromodulation and strengthening neural connectivity of the injured human spinal cord. Importantly, whether concurrent treatment with transspinal stimulation and locomotor training maximizes motor recovery after spinal cord injury is unknown. Methods Forty-five individuals with chronic spinal cord injury are receiving 40 sessions of robotic gait training primed with 30 Hz transspinal stimulation at the Thoracic 10 vertebral level. Participants are randomized to receive 30-minutes of active or sham transspinal stimulation during standing or active transspinal stimulation while supine followed by 30-minutes of robotic gait training. Over the course of locomotor training, the body weight support, treadmill speed, and leg guidance force are adjusted as needed for each participant based on absence of knee buckling during the stance phase and toe dragging during the swing phase. At baseline and after completion of all therapeutic sessions, neurophysiological recordings registering corticospinal and spinal neural excitability changes along with clinical assessment measures of standing and walking, and autonomic function via questionnaires regarding bowel, bladder and sexual function are taken. Discussion The results of this mechanistic randomized clinical trial will demonstrate that tonic transspinal stimulation strengthens corticomotoneuronal connectivity and dynamic neuromodulation through posture-dependent corticospinal and spinal neuroplasticity. We anticipate that this mechanistic clinical trial will greatly impact clinical practice because in real-world clinical settings, noninvasive transspinal stimulation can be more easily and widely implemented than invasive epidural stimulation. Additionally, by applying multiple interventions to accelerate motor recovery, we are employing a treatment regimen that reflects a true clinical approach. Trial registration ClinicalTrials.gov: NCT04807764; Registered on March 19, 2021.
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Affiliation(s)
| | | | | | - Parul Agrawal
- Icahn School of Medicine at Mount Sinai Department of Population Health Science and Policy
| | - Noam Y Harel
- James J Peters VAMC: James J Peters VA Medical Center
| | - Maria Knikou
- College of Staten Island School of Health Sciences
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Colard J, Jubeau M, Duclay J, Cattagni T. Regulation of primary afferent depolarization and homosynaptic post-activation depression during passive and active lengthening, shortening and isometric conditions. Eur J Appl Physiol 2023; 123:1257-1269. [PMID: 36781424 DOI: 10.1007/s00421-023-05147-x] [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: 12/08/2022] [Accepted: 01/26/2023] [Indexed: 02/15/2023]
Abstract
PURPOSE This study aimed to determine whether the modulation of primary afferent depolarization (PAD) and homosynaptic post-activation depression (HPAD) are involved in the lower efficacy of Ia-afferent-α-motoneuron transmission commonly observed during lengthening compared to isometric and shortening conditions. METHODS 15 healthy young individuals participated in two experimental sessions dedicated to measurement in passive and active muscle states, respectively. In each session, PAD, HPAD and the efficacy of Ia-afferent-α-motoneuron transmission were evaluated during lengthening, shortening and isometric conditions. PAD was evaluated with D1 inhibition technique. Posterior tibial nerve stimulation was used to study HPAD and the efficacy of the Ia-afferent-α-motoneuron transmission through the recording of the soleus Hoffmann reflex (H reflex). RESULTS PAD was increased in lengthening than shortening (11.2%) and isometric (12.3%) conditions regardless of muscle state (P < 0.001). HPAD was increased in lengthening than shortening (5.1%) and isometric (4.2%) conditions in the passive muscle state (P < 0.05), while no difference was observed in the active muscle state. H reflex was lower in lengthening than shortening (- 13.2%) and isometric (- 9.4%) conditions in both muscle states (P < 0.001). CONCLUSION These results highlight the specific regulation of PAD and HPAD during lengthening conditions. However, the differences observed during passive lengthening compared to shortening and isometric conditions seem to result from an increase in Ia-afferent discharge, while the variations highlighted during active lengthening might come from polysynaptic descending pathways involving supraspinal centres that could regulate PAD mechanism.
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Affiliation(s)
- Julian Colard
- Nantes University, Movement-Interactions-Performance, MIP, 25 Bis Boulevard Guy Mollet-BP 72206, UR 4334, 44322, Nantes, France
| | - Marc Jubeau
- Nantes University, Movement-Interactions-Performance, MIP, 25 Bis Boulevard Guy Mollet-BP 72206, UR 4334, 44322, Nantes, France.
| | - Julien Duclay
- Toulouse NeuroImaging Center, Université de Toulouse, Inserm, UPS, Toulouse, France
| | - Thomas Cattagni
- Nantes University, Movement-Interactions-Performance, MIP, 25 Bis Boulevard Guy Mollet-BP 72206, UR 4334, 44322, Nantes, France
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Pereira M, Fernandes SR, Miranda PC, de Carvalho M. Lumbar trans-spinal direct current stimulation: A modeling-experimental approach to dorsal root ganglia stimulation. Front Neurosci 2022; 16:1041932. [PMID: 36570853 PMCID: PMC9773993 DOI: 10.3389/fnins.2022.1041932] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 11/23/2022] [Indexed: 12/14/2022] Open
Abstract
Introduction The excitability of spinal motor neurons (MN) can be altered through subthreshold currents, such as transcutaneous spinal direct-current stimulation (tsDCS). Current evidence shows that tsDCS can interfere with ascending somatosensory pathways and lower motor neurons' (LMN) excitability, which points to its therapeutic potential for repairing altered spinal responses. We aim to define the best tsDCS montage for maximizing the electric field (E-field) in the lumbar spinal cord (L-SC) by computer modeling; and to apply this montage to measure the effect on LMN excitability and somatosensory evoked potentials (SSEP). Methods A human volume conductor model was obtained from an available database. The E-field distribution was calculated considering three different electrode settings aiming at maximizing the field at L-SC and right dorsal root ganglia (DRG). The best electrode setting was then selected and applied in a blind crossover pseudo-randomized study including 14 subjects. tsDCS was delivered for 15 min (cathodal vs. sham) over L2 vertebra level (4 mA, 144 mC/cm2), and its effect on F-waves, H-reflex (including homosynaptic depression, HD) and SSEPs was investigated in the lower limbs. Results All simulated montages showed higher current density and E-field magnitudes between the electrodes (>0.15 V/m), with a major longitudinal component and with rostral-caudal direction. The induced E-field involved the sensory ganglia and was maximum in the right T8-left L2 montage, which was the one selected for the experimental protocol. We disclosed a statistically significant increase of the H-reflex amplitude at 0.1 Hz, after cathodal tsDCS (c-tsDCS) on both sides. No other significant change was observed. Discussion Our results can suggest the c-tsDCS applied to the L-SC and DRG can modulate synaptic efficiency increasing lower motor neurons response to Ia fibers excitation. The possible implications of our findings for treating clinical conditions will be addressed in future studies.
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Affiliation(s)
- Mariana Pereira
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Sofia Rita Fernandes
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal,Instituto de Biofísica e Engenharia Biomédica, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
| | - Pedro Cavaleiro Miranda
- Instituto de Biofísica e Engenharia Biomédica, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
| | - Mamede de Carvalho
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal,Departamento de Neurociências e Saúde Mental, Hospital de Santa Maria - Centro Hospitalar Lisboa Norte, Lisboa, Portugal,*Correspondence: Mamede de Carvalho,
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Skiadopoulos A, Pulverenti TS, Knikou M. Physiological effects of cathodal electrode configuration for transspinal stimulation in humans. J Neurophysiol 2022; 128:1663-1682. [PMID: 36416443 PMCID: PMC9762966 DOI: 10.1152/jn.00342.2022] [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: 08/07/2022] [Revised: 11/16/2022] [Accepted: 11/17/2022] [Indexed: 11/24/2022] Open
Abstract
Transspinal stimulation modulates neuronal excitability and promotes recovery in upper motoneuron lesions. The recruitment input-output curves of transspinal evoked potentials (TEPs) recorded from knee and ankle muscles, and their susceptibility to spinal inhibition, were recorded when the position, size, and number of the cathode electrode were arranged in four settings or protocols (Ps). The four Ps were the following: 1) one rectangular electrode placed at midline (KNIKOU-LAB4Recovery or K-LAB4Recovery; P-KLAB), 2) one square electrode placed at midline (P-2), 3) two square electrodes 1 cm apart placed at midline (P-3), and 4) one square electrode placed on each paravertebral side (P-4). P-KLAB and P-3 required less current to reach TEP threshold or maximal amplitudes. A rightward shift in TEP recruitment curves was evident for P-4, whereas the slope was increased for P-2 and P-4 compared with P-KLAB and P-3. TEP depression upon single and paired transspinal stimuli was pronounced in ankle TEPs but was less prominent in knee TEPs. TEP depression induced by single transspinal stimuli at 1.0 Hz was similar for most TEPs across protocols, but TEP depression induced by paired transspinal stimuli was different between protocols and was replaced by facilitation at 100-ms interstimulus interval for P-4. Our results suggest that P-KLAB and P-3 are preferred based on excitability threshold of motoneurons. P-KLAB produced more TEP depression, thereby maximizing the engagement of spinal neuronal pathways. We recommend P-KLAB to study neurophysiological mechanisms underlying transspinal stimulation or when used as a neuromodulation method for recovery in neurological disorders.NEW & NOTEWORTHY Transspinal stimulation with a rectangular cathode electrode (P-KLAB) requires less current to produce transspinal evoked potentials and maximizes spinal inhibition. We recommend P-KLAB for neurophysiological studies or when used as a neuromodulation method to enhance motor output and normalize muscle tone in neurological disorders.
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Affiliation(s)
- Andreas Skiadopoulos
- Klab4Recovery Research Program, The City University of New York, New York, New York
| | - Timothy S Pulverenti
- Klab4Recovery Research Program, The City University of New York, New York, New York
| | - Maria Knikou
- Klab4Recovery Research Program, The City University of New York, New York, New York
- Department of Physical Therapy, College of Staten Island, The City University of New York, Staten Island, New York
- PhD Program in Biology and Collaborative Neuroscience Program, Graduate Center of The City University of New York and College of Staten Island, Staten Island, New York
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11
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Papitsa A, Paizis C, Papaiordanidou M, Martin A. Specific modulation of presynaptic and recurrent inhibition of the soleus muscle during lengthening and shortening submaximal and maximal contractions. J Appl Physiol (1985) 2022; 133:1327-1340. [PMID: 36356258 DOI: 10.1152/japplphysiol.00065.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The study analyzed neural mechanisms mediating spinal excitability modulation during eccentric (ECC) movement (passive muscle lengthening, submaximal, and maximal ECC contractions) as compared with concentric (CON) conditions. Twenty-two healthy subjects participated in three experiments. Experiment A (n = 13) examined D1 presynaptic inhibition (D1 PI) and recurrent inhibition (RI) modulation during passive muscle lengthening and shortening, by conditioning the soleus (SOL) H-reflex with common peroneal nerve submaximal and tibial nerve maximal stimulation, respectively. Experiment B (n = 13) analyzed the effect of passive muscle lengthening on D1 PI and heteronymous Ia facilitation (HF, conditioning the SOL H-reflex by femoral stimulation). Experiment C (n = 13) focused on the effect of muscle contraction level (20%, 50%, and 100% of maximal voluntary contraction) on D1 PI and RI. Results showed a significantly higher level of D1 PI during passive muscle lengthening than shortening (P < 0.01), whereas RI and HF were not affected by passive muscle movement. D1 PI and RI were both higher during ECC as compared with CON contractions (P < 0.001). However, the amount of D1 PI was independent of the torque level, whereas RI was reduced as the torque level increased (P < 0.05). The decreased spinal excitability induced by muscle lengthening during both passive and active conditions is mainly attributed to D1 PI, whereas RI also plays a role in the control of the specific motoneuron output during ECC contractions. Both inhibitory mechanisms are centrally controlled, but the fact that they evolve differently with torque increases, suggests a distinct supraspinal control.NEW & NOTEWORTHY Presynaptic (PI) and recurrent inhibitions (RI) were studied during passive muscle lengthening and eccentric contractions. Results indicate that the increased PI during passive muscle lengthening accounts for the decreased spinal excitability at rest. During eccentric contraction both mechanisms contribute to spinal excitability modulation. The same amount of PI was observed during eccentric contractions, while RI decreased as developed torque increased. This distinct modulation according to torque level suggests a distinct supraspinal control of these mechanisms.
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Affiliation(s)
- Athina Papitsa
- Department of Physical Education and Sport Sciences at Serres, Aristotle University of Thessaloniki, Thessaloniki Greece
| | - Christos Paizis
- Faculty of Sport Sciences, CAPS, INSERM U1093, University of Bourgogne Franche-Comté, Dijon, France.,Faculty of Sport Sciences, Centre for Performance Expertise, CAPS, U1093 INSERM, University of Bourgogne Franche-Comté, Dijon, France
| | - Maria Papaiordanidou
- Faculty of Sport Sciences, CAPS, INSERM U1093, University of Bourgogne Franche-Comté, Dijon, France
| | - Alain Martin
- Faculty of Sport Sciences, CAPS, INSERM U1093, University of Bourgogne Franche-Comté, Dijon, France
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12
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Papavasileiou A, Hatzitaki V, Mademli L, Patikas DA. Temporal modulation of H-reflex in young and older people: Acute effects during Achilles tendon vibration while standing. Exp Gerontol 2022; 165:111844. [DOI: 10.1016/j.exger.2022.111844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 03/20/2022] [Accepted: 05/23/2022] [Indexed: 11/04/2022]
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13
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Finn HT, Bogdanovski O, Hudson AL, McCaughey EJ, Crawford MR, Taylor JL, Butler JE, Gandevia SC. The effect of acute intermittent hypoxia on human limb motoneurone output. Exp Physiol 2022; 107:615-630. [PMID: 35338753 DOI: 10.1113/ep090099] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Accepted: 03/17/2022] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Does a single session of repeated bouts of acute intermittent hypoxic breathing enhance the motoneuronal output of the limb muscles of healthy able-bodied participants? What is the main finding and its importance? Compared to breathing room air, there were some increases in motoneuronal output following acute intermittent hypoxia, but the increases were variable across participants, in time after the intervention and depended on which neurophysiological measure was checked. ABSTRACT Acute intermittent hypoxia (AIH) induces persistent increases in output from rat phrenic motoneurones. Studies in people with spinal cord injury suggest AIH improves limb performance, perhaps via postsynaptic changes at cortico-motoneuronal synapses. We assessed whether limb motoneurone output in response to reflex and descending synaptic activation is facilitated after one session of AIH in healthy able-bodied volunteers. Fourteen participants completed two experimental days, either AIH or a sham intervention (randomised crossover design). We measured H-reflex recruitment curves and homosynaptic post-activation depression (HPAD) of the H reflex in soleus, and motor evoked potentials (MEPs) evoked by transcranial magnetic stimulation (TMS) and their recruitment curves, in first dorsal interosseous. All measurements were performed at rest and occurred at baseline, 0, 20, 40, and 60 minutes post-intervention. The intervention was 30 minutes of either normoxia (sham, FiO2 ≈ 0.21) or AIH (alternate 1-minute hypoxia [FiO2 ≈ 0.09], 1-minute normoxia). After AIH the H-reflex recruitment curve shifted leftward. Lower stimulation intensities were needed to evoke 5%, 50%, and 99% of the maximal H reflex at 40 and 60 minutes after AIH (P<0.04). The maximal H reflex, recruitment slope and HPAD, were unchanged after AIH. MEPs evoked by constant intensity TMS were larger 40 minutes after AIH (P = 0.027). There was no change in MEP recruitment or the maximal MEP. In conclusion, some measures of the evoked responses from limb motoneurones increased after a single AIH session, but only at discrete time points. It is unclear to what extent these changes alter functional performance. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Harrison T Finn
- Neuroscience Research Australia, Sydney, NSW, 2031, Australia.,University of New South Wales, Sydney, NSW, 2052, Australia
| | - Oliver Bogdanovski
- Neuroscience Research Australia, Sydney, NSW, 2031, Australia.,University of New South Wales, Sydney, NSW, 2052, Australia
| | - Anna L Hudson
- Neuroscience Research Australia, Sydney, NSW, 2031, Australia.,University of New South Wales, Sydney, NSW, 2052, Australia.,College of Medicine and Public Health, Flinders University, Bedford Park, South Australia, 5042, Australia
| | - Euan J McCaughey
- Neuroscience Research Australia, Sydney, NSW, 2031, Australia.,University of New South Wales, Sydney, NSW, 2052, Australia
| | | | - Janet L Taylor
- Neuroscience Research Australia, Sydney, NSW, 2031, Australia.,Edith Cowan University, Perth, WA, 6027, Australia
| | - Jane E Butler
- Neuroscience Research Australia, Sydney, NSW, 2031, Australia.,University of New South Wales, Sydney, NSW, 2052, Australia
| | - Simon C Gandevia
- Neuroscience Research Australia, Sydney, NSW, 2031, Australia.,University of New South Wales, Sydney, NSW, 2052, Australia
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14
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Corticospinal modulation of vibration-induced H-reflex depression. Exp Brain Res 2022; 240:803-812. [PMID: 35044475 PMCID: PMC8920763 DOI: 10.1007/s00221-022-06306-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 01/04/2022] [Indexed: 11/04/2022]
Abstract
The purpose of this study was to examine corticospinal modulation of spinal reflex excitability, by determining the effect of transcranial magnetic stimulation (TMS) on soleus H-reflexes while they were almost completely suppressed by lower extremity vibration. In 15 healthy adults, a novel method of single-limb vibration (0.6 g, 30 Hz, 0.33 mm displacement) was applied to the non-dominant leg. Soleus muscle responses were examined in six stimulation conditions: (1) H-reflex elicited by tibial nerve stimulation, (2) tibial nerve stimulation during vibration, (3) subthreshold TMS, (4) subthreshold TMS during vibration, (5) tibial nerve stimulation 10 ms after a subthreshold TMS pulse, and (6) tibial nerve stimulation 10 ms after a subthreshold TMS pulse, during vibration. With or without vibration, subthreshold TMS produced no motor evoked potentials and had no effect on soleus electromyography (p > 0.05). In the absence of vibration, H-reflex amplitudes were not affected by subthreshold TMS conditioning (median (md) 35, interquartile range (IQ) 18-56 vs. md 46, IQ 22-59% of the maximal M wave (Mmax), p > 0.05). During vibration, however, unconditioned H-reflexes were nearly abolished, and a TMS conditioning pulse increased the H-reflex more than fourfold (md 0.3, IQ 0.1-0.7 vs. md 2, IQ 0.9-5.0% of Mmax, p < 0.008). Limb vibration alone had no significant effect on corticospinal excitability. In the absence of vibration, a subthreshold TMS pulse did not influence the soleus H-reflex. During limb vibration, however, while the H-reflex was almost completely suppressed, a subthreshold TMS pulse partially restored the H-reflex. This disinhibition of the H-reflex by a corticospinal signal may represent a mechanism involved in the control of voluntary movement. Corticospinal signals that carry the descending motor command may also reduce presynaptic inhibition, temporarily increasing the impact of sensory inputs on motoneuron activation.
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15
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Kaneko N, Fok KL, Nakazawa K, Masani K. Motor point stimulation induces more robust F-waves than peripheral nerve stimulation. Eur J Neurosci 2022; 55:1614-1628. [PMID: 35178805 DOI: 10.1111/ejn.15625] [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: 08/20/2021] [Revised: 02/11/2022] [Accepted: 02/13/2022] [Indexed: 11/27/2022]
Abstract
The F-wave is a motor response induced by electrical stimulation of peripheral nerves via the antidromic firing of motor nerves, which reflects the motoneuron excitability. To induce F-waves, transcutaneous peripheral nerve stimulation (PNS) is used, which activates nerve branches via transcutaneous electrodes over the nerve branches. An alternative method to activate peripheral nerves, i.e., motor point stimulation (MPS) which delivers electrical stimulation over the muscle belly, has not been used to induce F-waves. In our previous studies, we observed that MPS induced F-wave like responses, i.e., motor responses at the latency of F-waves at a supramaximal stimulation. Here we further investigated the F-wave like responses induced by MPS in comparison to PNS in the soleus muscle. Thirteen individuals participated in this study. We applied MPS and PNS on the participant's left soleus muscle. Using a monopolar double-pulse stimulation, the amplitude of the second H-reflex induced by PNS decreased, while the amplitude of the motor response at the F-wave latency induced by MPS did not decrease. These results suggest that the motor response at the F-wave latency induced by MPS was not an H-reflex but an F-wave. We also found that the F-wave induced by MPS had a greater amplitude, higher persistence, and caused less pain when compared to the F-waves induced using PNS. We conclude that MPS evokes antidromic firing inducing F-waves more consistently compared to PNS.
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Affiliation(s)
- Naotsugu Kaneko
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada.,KITE - Toronto Rehabilitation Institute, University Health Network, Toronto, ON, Canada.,Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan.,Japan Society for the Promotion of Science, Tokyo, Japan
| | - Kai Lon Fok
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada.,KITE - Toronto Rehabilitation Institute, University Health Network, Toronto, ON, Canada
| | - Kimitaka Nakazawa
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Kei Masani
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada.,KITE - Toronto Rehabilitation Institute, University Health Network, Toronto, ON, Canada
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16
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Effect of Long-Term Classical Ballet Dance Training on Postactivation Depression of the Soleus Hoffmann-Reflex. Motor Control 2022; 26:169-180. [PMID: 34986460 DOI: 10.1123/mc.2021-0079] [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: 06/16/2021] [Revised: 11/01/2021] [Accepted: 11/05/2021] [Indexed: 11/18/2022]
Abstract
Classical ballet dancing is a good model for studying the long-term activity-dependent plasticity of the central nervous system in humans, as it requires unique ankle movements to maintain ballet postures. The purpose of this study was to investigate whether postactivation depression is changed through long-term specific motor training. Eight ballet dancers and eight sedentary subjects participated in this study. The soleus Hoffmann reflexes were elicited at after the completion of a slow, passive dorsiflexion of the ankle. The results demonstrated that the depression of the soleus Hoffmann reflex (i.e., postactivation depression) was larger in classical ballet dancers than in sedentary subjects at two poststretch intervals. This suggests that the plastic change through long-term specific motor training is also expressed in postactivation depression of the soleus Hoffmann reflex. Increased postactivation depression would strengthen the supraspinal control of the plantarflexors and may contribute to fine ankle movements in classical ballet dancers.
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17
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Pereira M, Swash M, de Carvalho M. Exercise following immobility increases lower motor neuron excitability: F-wave and H-reflex studies. Neurophysiol Clin 2022; 52:147-156. [PMID: 34996693 DOI: 10.1016/j.neucli.2021.12.004] [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: 08/25/2021] [Revised: 12/17/2021] [Accepted: 12/18/2021] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVES The excitability of lower motor neurons can be explored non-invasively by several neurophysiological techniques, e.g., F-wave and H-reflex studies after a period of immobility and then after subsequent exercise. The aim of this study is to investigate the impact of exercise and high frequency repetitive nerve stimulation (RNS) following changes induced by 75 min of immobility. METHODS We studied 10 healthy subjects following 75 min lower limb immobility, then randomized to RNS or cycling on different days. The neurophysiological studies of M-response, F-wave latency, F/M amplitude ratio and persistence; H-reflex threshold and latency, H/M amplitude ratio, and homosynaptic depression were performed at baseline, after immobility and immediately following the intervention, using stimulation of posterior tibial and peroneal nerves. RESULTS After immobility F-wave latencies were delayed and homosynaptic depression at 2 Hz was increased (p < 0.025). RNS had no effect, but cycling exercise reduced H-reflex latencies (p = 0.025) and decreased homosynaptic depression at 2 Hz. DISCUSSION Our findings suggest that both proprioceptive stimulation and supraspinal pathways modulate intraspinal physiological changes after immobility. These observations suggest that specific exercise protocols may be useful in managing patients recovering from periods of immobility.
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Affiliation(s)
- Mariana Pereira
- Instituto de Fisiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa. Lisbon, Portugal
| | - Michael Swash
- Instituto de Fisiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa. Lisbon, Portugal; Departments of Neurology and Neuroscience, Barts and the London School of Medicine, Queen Mary University of London and Royal London Hospital, UK
| | - Mamede de Carvalho
- Instituto de Fisiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa. Lisbon, Portugal; Department of Neurosciences and Mental Health, Hospital de Santa Maria, Centro Hospitalar Universitário de Lisboa Norte. Lisbon, Portugal.
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18
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Steele AG, Atkinson DA, Varghese B, Oh J, Markley RL, Sayenko DG. Characterization of Spinal Sensorimotor Network Using Transcutaneous Spinal Stimulation during Voluntary Movement Preparation and Performance. J Clin Med 2021; 10:jcm10245958. [PMID: 34945253 PMCID: PMC8709482 DOI: 10.3390/jcm10245958] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 12/10/2021] [Accepted: 12/15/2021] [Indexed: 12/12/2022] Open
Abstract
Transcutaneous electrical spinal stimulation (TSS) can be used to selectively activate motor pools based on their anatomical arrangements in the lumbosacral enlargement. These spatial patterns of spinal motor activation may have important clinical implications, especially when there is a need to target specific muscle groups. However, our understanding of the net effects and interplay between the motor pools projecting to agonist and antagonist muscles during the preparation and performance of voluntary movements is still limited. The present study was designed to systematically investigate and differentiate the multi-segmental convergence of supraspinal inputs on the lumbosacral neural network before and during the execution of voluntary leg movements in neurologically intact participants. During the experiments, participants (N = 13) performed isometric (1) knee flexion and (2) extension, as well as (3) plantarflexion and (4) dorsiflexion. TSS consisting of a pair pulse with 50 ms interstimulus interval was delivered over the T12-L1 vertebrae during the muscle contractions, as well as within 50 to 250 ms following the auditory or tactile stimuli, to characterize the temporal profiles of net spinal motor output during movement preparation. Facilitation of evoked motor potentials in the ipsilateral agonists and contralateral antagonists emerged as early as 50 ms following the cue and increased prior to movement onset. These results suggest that the descending drive modulates the activity of the inter-neuronal circuitry within spinal sensorimotor networks in specific, functionally relevant spatiotemporal patterns, which has a direct implication for the characterization of the state of those networks in individuals with neurological conditions.
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Affiliation(s)
- Alexander G. Steele
- Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, 6550 Fannin Street, Houston, TX 77030, USA; (A.G.S.); (D.A.A.); (B.V.); (J.O.); (R.L.M.)
- Department of Electrical and Computer Engineering, University of Houston, E413 Engineering Bldg 2, 4726 Calhoun Road, Houston, TX 77204, USA
| | - Darryn A. Atkinson
- Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, 6550 Fannin Street, Houston, TX 77030, USA; (A.G.S.); (D.A.A.); (B.V.); (J.O.); (R.L.M.)
- College of Rehabilitative Sciences, University of St. Augustine for Health Sciences, 5401 La Crosse Avenue, Austin, TX 78739, USA
| | - Blesson Varghese
- Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, 6550 Fannin Street, Houston, TX 77030, USA; (A.G.S.); (D.A.A.); (B.V.); (J.O.); (R.L.M.)
| | - Jeonghoon Oh
- Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, 6550 Fannin Street, Houston, TX 77030, USA; (A.G.S.); (D.A.A.); (B.V.); (J.O.); (R.L.M.)
| | - Rachel L. Markley
- Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, 6550 Fannin Street, Houston, TX 77030, USA; (A.G.S.); (D.A.A.); (B.V.); (J.O.); (R.L.M.)
| | - Dimitry G. Sayenko
- Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, 6550 Fannin Street, Houston, TX 77030, USA; (A.G.S.); (D.A.A.); (B.V.); (J.O.); (R.L.M.)
- Correspondence: ; Tel.: +1-713-363-9910
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19
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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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20
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Taki C, Nakata A, Shiozawa N, Kiyono K, Kimura T. Cross-correlated fractal components of H-wave amplitude fluctuations in medial gastrocnemius and soleus muscles. Neurosci Lett 2021; 765:136264. [PMID: 34563622 DOI: 10.1016/j.neulet.2021.136264] [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: 06/19/2021] [Revised: 09/15/2021] [Accepted: 09/21/2021] [Indexed: 10/20/2022]
Abstract
The time series of the H-wave amplitude in soleus muscle (SOL) shows fractal (long-range) correlation, which is attributed to input from supraspinal centers. However, whether such long-range power-law correlated input also contributes to the synergistic muscles remains unclear. The purpose of this study was therefore to examine the correlation in the fractal components of H-wave amplitude fluctuations between the synergistic muscles used for plantar flexion, i.e., the medial head of the gastrocnemius muscle (MG) and SOL. In eight young male participants, consecutive H-reflexes were recorded almost simultaneously from the MG and SOL at a stimulation frequency of 0.5 Hz for 30 min. We performed detrending moving-average cross-correlation analysis (DMCA) for each of the H- and M-wave amplitude time series between MG and SOL to assess the existence of a common noise input contributing to these long-range correlations. The cross-correlation coefficient ρDMCA (-1 to 1) was calculated to quantify the strength of the correlation between two different time series. The results indicated a significant long-range power-law correlation between H-wave amplitudes in MG and SOL (ρDMCA: 0.50 (0.22) and 0.22 (0.17), mean (standard deviation) for the original and randomly shuffled surrogate data, respectively, P < 0.05). This was not the case for M-wave amplitudes (ρDMCA: 0.29 (0.23) and 0.20 (0.15), P > 0.05). We conclude that there is a common noise input governing these synergistic muscles, possibly due to supraspinal origin, causing long-range power-law correlations in monosynaptic reflexes.
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Affiliation(s)
- Chinami Taki
- Graduate School of Sport and Health Science, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga 525-8577, Japan; Graduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Nada-ku, Kobe 657-8501, Japan; Division of Physical and Health Education, Setsunan University, 17-8 Ikedanakamachi, Neyagawa, Osaka 572-8508, Japan.
| | - Akio Nakata
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Naruhiro Shiozawa
- Faculty of Sport and Health Science, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga 525-8577, Japan
| | - Ken Kiyono
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Tetsuya Kimura
- Graduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Nada-ku, Kobe 657-8501, Japan
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21
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Al'joboori Y, Hannah R, Lenham F, Borgas P, Kremers CJP, Bunday KL, Rothwell J, Duffell LD. The Immediate and Short-Term Effects of Transcutaneous Spinal Cord Stimulation and Peripheral Nerve Stimulation on Corticospinal Excitability. Front Neurosci 2021; 15:749042. [PMID: 34744614 PMCID: PMC8566815 DOI: 10.3389/fnins.2021.749042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 09/27/2021] [Indexed: 12/17/2022] Open
Abstract
Rehabilitative interventions involving electrical stimulation show promise for neuroplastic recovery in people living with Spinal Cord Injury (SCI). However, the understanding of how stimulation interacts with descending and spinal excitability remain unclear. In this study we compared the immediate and short-term (within a few minutes) effects of pairing Transcranial Magnetic Stimulation (TMS) with transcutaneous Spinal Cord stimulation (tSCS) and Peripheral Nerve Stimulation (PNS) on Corticospinal excitability in healthy subjects. Three separate experimental conditions were assessed. In Experiment I, paired associative stimulation (PAS) was applied, involving repeated pairing of single pulses of TMS and tSCS, either arriving simultaneously at the spinal motoneurones (PAS0ms) or slightly delayed (PAS5ms). Corticospinal and spinal excitability, and motor performance, were assessed before and after the PAS interventions in 24 subjects. Experiment II compared the immediate effects of tSCS and PNS on corticospinal excitability in 20 subjects. Experiment III compared the immediate effects of tSCS with tSCS delivered at the same stimulation amplitude but modulated with a carrier frequency (in the kHz range) on corticospinal excitability in 10 subjects. Electromyography (EMG) electrodes were placed over the Tibialis Anterior (TA) soleus (SOL) and vastus medialis (VM) muscles and stimulation electrodes (cathodes) were placed on the lumbar spine (tSCS) and lateral to the popliteal fossa (PNS). TMS over the primary motor cortex (M1) was paired with tSCS or PNS to produce Motor Evoked Potentials (MEPs) in the TA and SOL muscles. Simultaneous delivery of repetitive PAS (PAS0ms) increased corticospinal excitability and H-reflex amplitude at least 5 min after the intervention, and dorsiflexion force was increased in a force-matching task. When comparing effects on descending excitability between tSCS and PNS, a subsequent facilitation in MEPs was observed following tSCS at 30-50 ms which was not present following PNS. To a lesser extent this facilitatory effect was also observed with HF- tSCS at subthreshold currents. Here we have shown that repeated pairing of TMS and tSCS can increase corticospinal excitability when timed to arrive simultaneously at the alpha-motoneurone and can influence functional motor output. These results may be useful in optimizing stimulation parameters for neuroplasticity in people living with SCI.
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Affiliation(s)
- Yazi Al'joboori
- Department of Medical Physics & Biomedical Engineering, University College London, London, United Kingdom
| | - Ricci Hannah
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom
| | - Francesca Lenham
- Department of Medical Physics & Biomedical Engineering, University College London, London, United Kingdom
| | - Pia Borgas
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom
| | - Charlotte J P Kremers
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom
| | - Karen L Bunday
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom.,Psychology, School of Social Sciences, University of Westminster, London, United Kingdom
| | - John Rothwell
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom
| | - Lynsey D Duffell
- Department of Medical Physics & Biomedical Engineering, University College London, London, United Kingdom
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22
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Heinke LN, Knicker AJ, Albracht K. Test-Retest reliability of the internal shoulder rotator muscles' stretch reflex in healthy men. J Electromyogr Kinesiol 2021; 62:102611. [PMID: 34800872 DOI: 10.1016/j.jelekin.2021.102611] [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: 07/02/2021] [Revised: 10/07/2021] [Accepted: 10/29/2021] [Indexed: 10/19/2022] Open
Abstract
Until now the reproducibility of the short latency stretch reflex of the internal rotator muscles of the glenohumeral joint has not been identified. Twenty-three healthy male participants performed three sets of external shoulder rotation stretches with various pre-activation levels on two different dates of measurement to assess test-retest reliability. All stretches were applied with a dynamometer acceleration of 104°/s2 and a velocity of 150°/s. Electromyographical response was measured via surface EMG. Reflex latencies showed a pre-activation effect (ƞ2 = 0,355). ICC ranged from 0,735 to 0,909 indicating an overall "good" relative reliability. SRD 95% lay between ±7,0 to ±12,3 ms. The reflex gain showed overall poor test-retest reproducibility. The chosen methodological approach presented a suitable test protocol for shoulder muscles stretch reflex latency evaluation. A proof-of-concept study to validate the presented methodical approach in shoulder involvement including subjects with clinically relevant conditions is recommended.
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Affiliation(s)
- Lars N Heinke
- Institute of Movement and Neuroscience, German Sports University, Cologne, Germany.
| | - Axel J Knicker
- Institute of Movement and Neuroscience, German Sports University, Cologne, Germany
| | - Kirsten Albracht
- Institute of Movement and Neuroscience, German Sports University, Cologne, Germany; Faculty of Medical Engineering and Technomathematics, FH Aachen University of Applied Sciences, Aachen, Germany
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23
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Effects of Ankle Continuous Passive Motion on Soleus Hypertonia in Individuals with Cerebral Palsy: A Case Series. Biomed J 2021; 45:708-716. [PMID: 34332162 PMCID: PMC9486241 DOI: 10.1016/j.bj.2021.07.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 07/19/2021] [Accepted: 07/23/2021] [Indexed: 11/23/2022] Open
Abstract
Background Continuous passive motion device (CPM) provides repetitive movement over extended periods of time for those who have low functional ability. The purpose of this research was to evaluate the effects of a four-week program of continuous passive motion of the ankle joint on the changes in soleus hypertonia in individuals with cerebral palsy who suffered from life-long hypertonia. Methods A single group, repeated-measures study was conducted. Eight individuals (7 males and 1 female with a mean age of 21.8 ± 8.5 years) with spastic cerebral palsy underwent bilateral ankle CPM for 1 h a day, 5 days a week, for 4 weeks. The outcome measures included the Modified Ashworth Scale (MAS) score, passive range of motion (PROM) of the ankle, the ratio of maximum H reflex to maximum soleus M-response (H/M ratio), and post-activation depression (PAD). All outcomes were measured before and after the intervention. A paired t-test was used to examine treatment effects pre-versus post-intervention. Results Paired t-tests showed that the CPM program significantly decreased the MAS score (p = 0.006), decreased the maximum H/M ratio (p=0.001), improved PAD (p = 0.003, p = 0.040, and p = 0.032 at 0.2 Hz, 1 Hz, and 2 Hz, respectively), and increased the passive ankle range of motion (p = 0.049). Conclusion Ankle CPM not only reduced soleus hypertonia but also improved the PROM in individuals with cerebral palsy. The results of this study show ankle CPM to be an effective intervention for individuals with cerebral palsy.
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24
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Sharma P, Shah PK. In vivo electrophysiological mechanisms underlying cervical epidural stimulation in adult rats. J Physiol 2021; 599:3121-3150. [PMID: 33894695 DOI: 10.1113/jp281146] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 03/15/2021] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS To electrophysiologically determine the predominant neural structures activated with cervical epidural stimulation (ES), well-established electrophysiological protocols (single-pulse, paired-pulse and multiple frequency stimulation) were delivered at rest, during motor activity and under anaesthesia in adult rats. Cervical ES resulted in spinal evoked motor responses with three different waveforms - early response (ER), middle response (MR) and late response (LR). ERs remained unmodulated by repeated stimulation protocols. In contrast, MRs and LRs were modulated by repeated stimulation protocols and volitional motor activity. ERs are consequential to the direct activation of motor efferents; MRs are secondary to type-I sensory afferent activation and LRs result from the engagement of wider spinal interneuronal circuitry with potential influence from supraspinal pathways. Evidence from this work is fundamental in enhancing our understanding of cervical ES, and critical in refining the design of neuromodulation-based rehabilitative strategies and in the construction of neuroprosthetics. ABSTRACT Epidural stimulation (ES) of the lumbar spinal cord has demonstrated significant improvements in various physiological functions after a traumatic spinal cord injury in humans. Electrophysiological evidence from rodent, human and computational studies collectively suggest that the functional recovery following lumbar ES is mediated via direct activation of sensory afferent fibres. However, the mechanisms underlying cervical ES have not been comprehensively studied, which greatly limits our understanding of its effectiveness in restoring upper limb function. In this work, we determined the predominant neural structures that are activated with cervical ES using in vivo cervical spinal evoked motor responses (SEMRs). Standard electrophysiological protocols (single-pulse, paired-pulse and multiple frequency stimulation) were implemented in 11 awake and anaesthetized rats in four experimental stages. Three distinct types of cervical SEMRs were identified based on latency of their appearance: early response (ER), middle response (MR) and late response (LR). ERs remained unmodulated by repeated stimulation protocols. MRs and LRs were modulated by repeated stimulation protocols and volitional motor activity. Except for LRs being completely abolished under urethane, ketamine or urethane anaesthesia did not affect the appearance of cervical SEMRs. Our data, backed by literature, suggest that ERs are secondary to the direct activation of motor efferents, MRs are elicited by activation of type-I sensory afferents and LRs result from the engagement of interneuronal circuitry with potential influence from supraspinal pathways. The gathered information paves the way to designing motor rehabilitation strategies that can utilize cervical ES to recover upper limb function following neurological deficits.
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Affiliation(s)
- Pawan Sharma
- Division of Rehabilitation Sciences, Department of Physical Therapy, School of Health Technology and Management, Stony Brook University, Stony Brook, NY, 11727, USA
| | - Prithvi K Shah
- Division of Rehabilitation Sciences, Department of Physical Therapy, School of Health Technology and Management, Stony Brook University, Stony Brook, NY, 11727, USA
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25
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Leukel C, Kurz A. Determining the types of descending waves from transcranial magnetic stimulation measured with conditioned H-reflexes in humans. Eur J Neurosci 2021; 54:5038-5046. [PMID: 33966324 DOI: 10.1111/ejn.15308] [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: 10/17/2020] [Revised: 04/09/2021] [Accepted: 05/02/2021] [Indexed: 11/30/2022]
Abstract
Non-invasive techniques are scarce with which human (motor) cortical mechanisms can be investigated. In a series of previous experiments, we have applied an advanced form of conditioning technique with transcranial magnetic stimulation (TMS) and peripheral nerve stimulation by which excitability changes at the laminar level in the primary motor cortex can be estimated. This method builds on the assumption that the first of subsequent corticospinal waves from TMS which is assessed with H-reflexes (called early facilitation) results from indirect excitation of corticospinal neurons in motor cortex (I-wave) and not direct excitation of corticospinal axons (D-wave). So far, we have not provided strong experimental evidence that this is actually the case. In the present study, we therefore compared temporal differences of the early facilitation between transcranial magnetic and electrical stimulation (TES). TES is known to excite the axons of corticospinal neurons. TES in our study caused a temporal shift of the early facilitation of H-reflexes in all subjects compared to TMS, which indicates that the early facilitation with TMS is indeed produced by an I-wave. Additionally, we investigated temporal shifts of the early facilitation with different TMS intensities and two TMS coils. It has long been known that TMS with higher intensities can induce a D-wave. Accordingly, we found that TMS with an intensity of 150% of resting motor threshold compared to 130%/110% results in a temporal shift of the early facilitation, indicating the presence of a D-wave. This effect was dependent on the coil type.
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Affiliation(s)
- Christian Leukel
- Department of Sport Science, University of Freiburg, Freiburg, Germany.,Bernstein Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Alexander Kurz
- Department of Sport Science, University of Freiburg, Freiburg, Germany.,Bernstein Center Freiburg, University of Freiburg, Freiburg, Germany
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26
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Bilchak JN, Yeakle K, Caron G, Malloy D, Côté MP. Enhancing KCC2 activity decreases hyperreflexia and spasticity after chronic spinal cord injury. Exp Neurol 2021; 338:113605. [PMID: 33453210 PMCID: PMC7904648 DOI: 10.1016/j.expneurol.2021.113605] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/21/2020] [Accepted: 01/09/2021] [Indexed: 02/03/2023]
Abstract
After spinal cord injury (SCI), the majority of individuals develop spasticity, a debilitating condition involving involuntary movements, co-contraction of antagonistic muscles, and hyperreflexia. By acting on GABAergic and Ca2+-dependent signaling, current anti-spastic medications lead to serious side effects, including a drastic decrease in motoneuronal excitability which impairs motor function and rehabilitation efforts. Exercise, in contrast, decreases spastic symptoms without decreasing motoneuron excitability. These functional improvements coincide with an increase in expression of the chloride co-transporter KCC2 in lumbar motoneurons. Thus, we hypothesized that spastic symptoms can be alleviated directly through restoration of chloride homeostasis and endogenous inhibition by increasing KCC2 activity. Here, we used the recently developed KCC2 enhancer, CLP257, to evaluate the effects of acutely increasing KCC2 extrusion capability on spastic symptoms after chronic SCI. Sprague Dawley rats received a spinal cord transection at T12 and were either bike-trained or remained sedentary for 5 weeks. Increasing KCC2 activity in the lumbar enlargement improved the rate-dependent depression of the H-reflex and reduced both phasic and tonic EMG responses to muscle stretch in sedentary animals after chronic SCI. Furthermore, the improvements due to this pharmacological treatment mirror those of exercise. Together, our results suggest that pharmacologically increasing KCC2 activity is a promising approach to decrease spastic symptoms in individuals with SCI. By acting to directly restore endogenous inhibition, this strategy has potential to avoid severe side effects and improve the quality of life of affected individuals.
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Affiliation(s)
- Jadwiga N Bilchak
- Marion Murray Spinal Cord Injury Research Center, Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, United States of America
| | - Kyle Yeakle
- Marion Murray Spinal Cord Injury Research Center, Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, United States of America
| | - Guillaume Caron
- Marion Murray Spinal Cord Injury Research Center, Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, United States of America
| | - Dillon Malloy
- Marion Murray Spinal Cord Injury Research Center, Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, United States of America
| | - Marie-Pascale Côté
- Marion Murray Spinal Cord Injury Research Center, Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, United States of America.
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27
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Hofstoetter US, Danner SM, Freundl B, Binder H, Lackner P, Minassian K. Ipsi- and Contralateral Oligo- and Polysynaptic Reflexes in Humans Revealed by Low-Frequency Epidural Electrical Stimulation of the Lumbar Spinal Cord. Brain Sci 2021; 11:brainsci11010112. [PMID: 33467053 PMCID: PMC7830402 DOI: 10.3390/brainsci11010112] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/11/2021] [Accepted: 01/12/2021] [Indexed: 01/16/2023] Open
Abstract
Epidural electrical stimulation (EES) applied over the human lumbosacral spinal cord provides access to afferent fibers from virtually all lower-extremity nerves. These afferents connect to spinal networks that play a pivotal role in the control of locomotion. Studying EES-evoked responses mediated through these networks can identify some of their functional components. We here analyzed electromyographic (EMG) responses evoked by low-frequency (2–6 Hz) EES derived from eight individuals with chronic, motor complete spinal cord injury. We identified and separately analyzed three previously undescribed response types: first, crossed reflexes with onset latencies of ~55 ms evoked in the hamstrings; second, oligosynaptic reflexes within 50 ms post-stimulus superimposed on the monosynaptic posterior root-muscle reflexes in the flexor muscle tibialis anterior, but with higher thresholds and no rate-sensitive depression; third, polysynaptic responses with variable EMG shapes within 50–450 ms post-stimulus evoked in the tibialis anterior and triceps surae, some of which demonstrated consistent changes in latencies with graded EES. Our observations suggest the activation of commissural neurons, lumbar propriospinal interneurons, and components of the late flexion reflex circuits through group I and II proprioceptive afferent inputs. These potential neural underpinnings have all been related to spinal locomotion in experimental studies.
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Affiliation(s)
- Ursula S. Hofstoetter
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, 1090 Vienna, Austria;
| | - Simon M. Danner
- Department of Neurobiology and Anatomy, College of Medicine, Drexel University, Philadelphia, PA 19129, USA;
| | - Brigitta Freundl
- Neurological Center, Klinik Penzing—Wiener Gesundheitsverbund, 1140 Vienna, Austria; (B.F.); (H.B.); (P.L.)
| | - Heinrich Binder
- Neurological Center, Klinik Penzing—Wiener Gesundheitsverbund, 1140 Vienna, Austria; (B.F.); (H.B.); (P.L.)
| | - Peter Lackner
- Neurological Center, Klinik Penzing—Wiener Gesundheitsverbund, 1140 Vienna, Austria; (B.F.); (H.B.); (P.L.)
| | - Karen Minassian
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, 1090 Vienna, Austria;
- Correspondence:
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28
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Mesquita RNO, Taylor JL, Kirk B, Blazevich AJ. Involuntary sustained firing of plantar flexor motor neurones: effect of electrical stimulation parameters during tendon vibration. Eur J Appl Physiol 2021; 121:881-891. [PMID: 33392744 PMCID: PMC7892516 DOI: 10.1007/s00421-020-04563-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 11/16/2020] [Indexed: 11/28/2022]
Abstract
PURPOSE Simultaneous application of tendon vibration and neuromuscular electrical stimulation (NMES) induces an involuntary sustained torque. We examined the effect of different NMES parameters (intensity, pattern of stimulation and pulse width) on the magnitude of the evoked involuntary torque. METHODS Plantar flexor torque was recorded during 33-s Achilles tendon vibration with simultaneous 20-Hz NMES bouts on triceps surae (n = 20; 13 women). Intensity was set to elicit 10, 20 or 30% of maximal voluntary contraction torque (MVC), pulse width was narrow (0.2 ms) or wide (1 ms), and the stimulus pattern varied (5 × 2-s or 10 × 1-s). Up to 12 different trials were performed in a randomized order, and then repeated in those who produced a sustained involuntary torque after the cessation of vibration. RESULTS Six of 7 men and 5 of 13 women produced a post-vibration sustained torque. Eight of 20 participants did not complete the 30% trials, as they were perceived as painful. Torque during vibration at the end of NMES and the increase in torque throughout the trial were significantly higher in 20 than 10% trials (n = 11; 9.7 ± 9.0 vs 7.1 ± 6.1% MVC and 4.3 ± 4.5 vs 3.6 ± 3.5% MVC, respectively). Post-vibration sustained torque was higher in wide pulse-width trials (5.4 ± 5.9 vs 4.1 ± 4.3% MVC). Measures of involuntary torque were not different between 20 and 30% trials (n = 8). CONCLUSION Bouts of 5 × 2-s NMES with wide pulse width eliciting 20% MVC provides the most robust responses and could be used to maximise the production of involuntary torque in triceps surae.
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Affiliation(s)
- Ricardo N O Mesquita
- Centre for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, Perth, Australia.
| | - Janet L Taylor
- Centre for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, Perth, Australia.,Neuroscience Research Australia, Sydney, Australia
| | - Benjamin Kirk
- Centre for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, Perth, Australia
| | - Anthony J Blazevich
- Centre for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, Perth, Australia
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Andrews JC, Roy FD, Stein RB, Ba F, Sankar T. Effect of Motor State on Postactivation Depression of the Soleus H-Reflex in Parkinson's Disease During Deep Brain Stimulation and Dopaminergic Medication Treatment: A Pilot Study. J Clin Neurophysiol 2020; 39:497-503. [PMID: 33394822 DOI: 10.1097/wnp.0000000000000808] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PURPOSE Postactivation depression of the Hoffmann reflex is reduced in Parkinson's disease (PD), but how the recovery is influenced by the state of the muscle is unknown. The present pilot study examined postactivation depression in PD at rest and during a voluntary contraction while patients were off treatment and while receiving medications and/or deep brain stimulation. METHODS The authors recruited nine patients with PD treated with implanted deep brain stimulation and examined postactivation depression under four treatment conditions. Paired pulses were delivered 25 to 300 ms apart, and soleus Hoffmann reflex recovery was tested at rest and during voluntary plantar flexion. Trials were matched for background muscle activity and compared with 10 age-matched controls. RESULTS Patients with Parkinson disease who were OFF medications (OFF meds) and OFF stimulation (OFF stim) at rest showed less postactivation depression at the 300 ms interpulse interval (86.1% ± 21.0%) relative to control subjects (36.4% ± 6.1%; P < 0.05). Postactivation depression was restored when dopaminergic medication and/or deep brain stimulation was applied. Comparisons between resting and active motor states revealed that the recovery curves were similar OFF meds/OFF stim owing to faster recovery in PD seen at rest. In contrast, the effect of the motor state was different ON meds/OFF stim and ON meds/ON stim (both P < 0.05), with a nonsignificant trend OFF meds/ON stim (P > 0.08). During a contraction, recovery curves were similar between all treatment conditions in PD and control. CONCLUSIONS Disrupted Hoffmann reflex recovery is restored to control levels in PD patients at rest when receiving medications and/or deep brain stimulation or when engaged in voluntary contraction.
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Affiliation(s)
- Jennifer C Andrews
- Departments of Surgery and Physiology, University of Alberta, Edmonton, AB, Canada; and Divisions of Neurology and Neurosurgery, University of Alberta, Edmonton, AB, Canada
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30
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Amyotrophic lateral sclerosis weakens spinal recurrent inhibition and post-activation depression. Clin Neurophysiol 2020; 131:2875-2886. [DOI: 10.1016/j.clinph.2020.09.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 08/15/2020] [Accepted: 09/07/2020] [Indexed: 01/07/2023]
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31
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Harmsen JF, Latella C, Mesquita R, Fasse A, Schumann M, Behringer M, Taylor J, Nosaka K. H-reflex and M-wave responses after voluntary and electrically evoked muscle cramping. Eur J Appl Physiol 2020; 121:659-672. [PMID: 33245422 DOI: 10.1007/s00421-020-04560-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 11/10/2020] [Indexed: 11/28/2022]
Abstract
PURPOSE Despite the widespread occurrence of muscle cramps, their underlying neurophysiological mechanisms remain unknown. To better understand the etiology of muscle cramps, this study investigated acute effects of muscle cramping induced by maximal voluntary isometric contractions (MVIC) and neuromuscular electrical stimulation (NMES) on the amplitude of Hoffmann reflexes (H-reflex) and compound muscle action potentials (M-wave). METHODS Healthy men (n = 14) and women (n = 3) participated in two identical sessions separated by 7 days. Calf muscle cramping was induced by performing MVIC of the plantar flexors in a prone position followed by 2.5-s NMES over the plantar flexors with increasing frequency and intensity. H-reflexes and M-waves evoked by tibial nerve stimulation in gastrocnemius medialis (GM) and soleus were recorded at baseline, and after MVIC-induced cramps and the NMES protocol. RESULTS Six participants cramped after MVIC, and H-reflex amplitude decreased in GM and soleus in Session 1 (- 33 ± 32%, - 34 ± 33%, p = 0.031) with a similar trend in Session 2 (5 cramped, p = 0.063), whereas the maximum M-wave was unchanged. After NMES, 11 (Session 1) and 9 (Session 2) participants cramped. H-reflex and M-wave recruitment curves shifted to the left in both sessions and muscles after NMES independent of cramping (p ≤ 0.001). CONCLUSION Changes in H-reflexes after a muscle cramp induced by MVIC and NMES were inconsistent. While MVIC-induced muscle cramps reduced H-reflex amplitude, muscle stretch to end cramping was a potential contributing factor. By contrast, NMES may potentiate H-reflexes and obscure cramp-related changes. Thus, the challenge for future studies is to separate the neural consequences of cramping from methodology-based effects.
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Affiliation(s)
- Jan-Frieder Harmsen
- Department of Molecular and Cellular Sports Medicine, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933, Cologne, Germany.
- Department of Nutrition and Movement Sciences, School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands.
| | - Christopher Latella
- Center for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia
- Neurophysiology Research Laboratory, Edith Cowan University, Joondalup, WA, Australia
| | - Ricardo Mesquita
- Center for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia
| | | | - Moritz Schumann
- Department of Molecular and Cellular Sports Medicine, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933, Cologne, Germany
| | - Michael Behringer
- Faculty of Sport Sciences, Goethe University Frankfurt, Frankfurt, Germany
| | - Janet Taylor
- Center for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia
- Neurophysiology Research Laboratory, Edith Cowan University, Joondalup, WA, Australia
| | - Kazunori Nosaka
- Center for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia
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32
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Franz KS, Patel K, Kilkenny DM. A biomedical Engineering Laboratory module for exploring involuntary muscle reflexes using Electromyography. J Biol Eng 2020; 14:26. [PMID: 33292462 PMCID: PMC7650172 DOI: 10.1186/s13036-020-00248-z] [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: 07/02/2020] [Accepted: 10/29/2020] [Indexed: 11/10/2022] Open
Abstract
Background Undergraduate biomedical engineering (BME) students interested in pursuing a career in research and development of medical or physiological monitoring devices require a strong foundation in biosignal analysis as well as physiological theory. Applied learning approaches are reported to be effective for reinforcing physiological coursework; therefore, we propose a new laboratory protocol for BME undergraduate physiology courses that integrates both neural engineering and physiological concepts to explore involuntary skeletal muscle reflexes. The protocol consists of two sections: the first focuses on recruiting soleus motor units through transcutaneous electrical nerve stimulation (TENS), while the second focuses on exploring the natural stretch reflex with and without the Jendrassik maneuver. In this case study, third-year biomedical engineering students collected electromyographic (EMG) activity of skeletal muscle contractions in response to peripheral nerve stimulation using a BioRadio Wireless Physiology Monitor system and analyzed the corresponding signal parameters (latency and amplitude) using the MATLAB platform. Results/protocol validation Electrical tibial nerve stimulation successfully recruited M-waves in all 8 student participants and F-waves in three student participants. The students used this data to learn about orthodromic and antidromic motor fiber activation as well as estimate the neural response latency and amplitude. With the stretch reflex, students were able to collect distinct signals corresponding to the tendon strike and motor response. From this, they were able to estimate the sensorimotor conduction velocity. Additionally, a significant increase in the stretch reflex EMG amplitude response was observed when using the Jendrassik maneuver during the knee-jerk response. A student exit survey on the laboratory experience reported that the class found the module engaging and helpful for reinforcing physiological course concepts. Conclusion This newly developed protocol not only allows BME students to explore physiological responses using natural and electrically-induced involuntary reflexes, but demonstrates that budget-friendly commercially available devices are capable of eliciting and measuring involuntary reflexes in an engaging manner. Despite some limitations caused by the equipment and students’ lack of signal processing experience, this new laboratory protocol provides a robust framework for integrating engineering and physiology in an applied approach for BME students to learn about involuntary reflexes, neurophysiology, and neural engineering. Supplementary Information The online version contains supplementary material available at 10.1186/s13036-020-00248-z.
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Affiliation(s)
- Karly S Franz
- Institute of Biomedical Engineering, University of Toronto, 164 College St Room 407, Toronto, ON, M5S 3G9, Canada.,Bloorview Research Institute, Holland Bloorview Kids Rehabilitation, 150 Kilgour Rd, East York, ON, M4G 1R8, Canada
| | - Kramay Patel
- Institute of Biomedical Engineering, University of Toronto, 164 College St Room 407, Toronto, ON, M5S 3G9, Canada.,Krembil Research Institute, 60 Leonard Avenue, Toronto, ON, M5T 0S8, Canada.,Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Dawn M Kilkenny
- Institute of Biomedical Engineering, University of Toronto, 164 College St Room 407, Toronto, ON, M5S 3G9, Canada. .,Institute for Studies in Transdisciplinary Engineering Education & Practice, University of Toronto, 35 St. George Street, Toronto, ON, M5S 1A4, Canada.
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Andrews JC, Roy FD, Ba F, Sankar T. Intraoperative changes in the H-reflex pathway during deep brain stimulation surgery for Parkinson's disease: A potential biomarker for optimal electrode placement. Brain Stimul 2020; 13:1765-1773. [PMID: 33035725 DOI: 10.1016/j.brs.2020.09.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 07/21/2020] [Accepted: 09/29/2020] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Deep Brain Stimulation (DBS) targeting the subthalamic nucleus (STN) and globus pallidus interna (GPi) is an effective treatment for cardinal motor symptoms and motor complications in Parkinson's Disease (PD). However, malpositioned DBS electrodes can result in suboptimal therapeutic response. OBJECTIVE We explored whether recovery of the H-reflex-an easily measured electrophysiological analogue of the stretch reflex, known to be altered in PD-could serve as an adjunct biomarker of suboptimal versus optimal electrode position during STN- or GPi-DBS implantation. METHODS Changes in soleus H-reflex recovery were investigated intraoperatively throughout awake DBS target refinement across 26 nuclei (14 STN). H-reflex recovery was evaluated during microelectrode recording (MER) and macrostimulation at multiple locations within and outside target nuclei, at varying stimulus intensities. RESULTS Following MER, H-reflex recovery normalized (i.e., became less Parkinsonian) in 21/26 nuclei, and correlated with on-table motor improvement consistent with an insertional effect. During macrostimulation, H-reflex recovery was maximally normalized in 23/26 nuclei when current was applied at the location within the nucleus producing optimal motor benefit. At these optimal sites, H-reflex normalization was greatest at stimulation intensities generating maximum motor benefit free of stimulation-induced side effects, with subthreshold or suprathreshold intensities generating less dramatic normalization. CONCLUSION H-reflex recovery is modulated by stimulation of the STN or GPi in patients with PD and varies depending on the location and intensity of stimulation within the target nucleus. H-reflex recovery shows potential as an easily-measured, objective, patient-specific, adjunct biomarker of suboptimal versus optimal electrode position during DBS surgery for PD.
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Affiliation(s)
| | - François D Roy
- Department of Surgery, University of Alberta, Edmonton, Canada
| | - Fang Ba
- Division of Neurology, University of Alberta, Edmonton, Canada
| | - Tejas Sankar
- Department of Surgery, University of Alberta, Edmonton, Canada; Division of Neurosurgery, University of Alberta, Edmonton, Canada.
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Özyurt MG, Topkara B, Şenocak BS, Budan AS, Yüce MN, Türker KS. Post-activation depression of primary afferents reevaluated in humans. J Electromyogr Kinesiol 2020; 54:102460. [PMID: 32905963 DOI: 10.1016/j.jelekin.2020.102460] [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: 05/16/2020] [Revised: 08/05/2020] [Accepted: 08/19/2020] [Indexed: 11/26/2022] Open
Abstract
Amplitude variation of Hoffmann Reflex (H-reflex) was used as a tool to investigate many neuronal networks. However, H-reflex itself is a subject to intrinsic changes including post-activation depression (P-AD). We aimed to investigate P-AD and its implication on motor control in humans. Upon tibial nerve stimulation in 23 healthy participants, peak-to-peak amplitude change of H-reflex was investigated using surface electromyography (SEMG) of soleus muscle. Variety of stimulus intensities, interstimulus intervals (ISIs), voluntary contraction levels/types and force recording were used to investigate the nature of P-AD. We have shown that P-AD was significantly stronger in the shorter ISIs. The only exception was the ISI of 200 msecs which had a weaker P-AD than some of the longer ISIs. Sudden muscle relaxation, on the other hand, further increased the effectiveness of the ongoing P-AD. Moreover, P-AD displayed its full effect with the first stimulus when there was no muscle contraction and was efficient to reduce the muscle force output by about 30%. These findings provide insight about the variations and mechanism of P-AD and could lead to improvements in diagnostic tools in neurological diseases.
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Affiliation(s)
| | - Betilay Topkara
- Koç University, School of Medicine, 34450 Sariyer, Istanbul, Turkey
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Yurttutmuş Z, Ekici Zincirci D, Bardak AN, Topkara B, Aydın T, Karacan I, Türker KS. A stimulus rate that is not influenced by homosynaptic post-activation depression in chronic stroke. Somatosens Mot Res 2020; 37:271-276. [PMID: 32811248 DOI: 10.1080/08990220.2020.1807925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
PURPOSE To determine a stimulus rate that is not influenced by homosynaptic post-activation depression for H-reflex studies in patients with chronic spasticity. MATERIALS AND METHODS A cohort of 15 chronic stroke patients with soleus spasticity who received inpatient treatment at our rehabilitation centre participated in this study. The effect of stimulus frequency related depression on H-reflex size was tested using four different stimulus rates (0.1, 0.2, 0.3 and 1 Hz). The affected sides stibial nerve was stimulated by a bipolar electrode. The H-reflex was recorded from the affected sideed sidee sidehe affected smine stimulus frequency related depression of H-reflex size, amplitude of the first H-reflex response (H1) was used as control and amplitude of the second H-reflex response (H2) as test. RESULTS H2 amplitude for frequency of 1 Hz, 0.3 Hz, 0.2 Hz and 0.1 Hz were 74.3, 84.1, 85.5 and 92.7% of H1, respectively. Depression of H2 amplitude was statistically significant for 1 Hz, 0.3 Hz and 0.2 Hz (p < 0.001, p = 0.002, p = 0.024, respectively). CONCLUSIONS Higher frequency stimulation of Ia afferents than 0.1 Hz induced a stimulus frequency-related depression of H-reflex size in patients with chronic spasticity. The optimal stimulus rate for H-reflex was found to be 0.1 Hz.
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Affiliation(s)
- Zeynep Yurttutmuş
- Istanbul Physical Therapy Rehabilitation Training and Research Hospital, Istanbul, Turkey
| | - Dilara Ekici Zincirci
- Istanbul Physical Therapy Rehabilitation Training and Research Hospital, Istanbul, Turkey
| | - Ayse Nur Bardak
- Istanbul Physical Therapy Rehabilitation Training and Research Hospital, Istanbul, Turkey
| | - Betilay Topkara
- Physiology Department, Koç University School of Medicine, Istanbul, Turkey
| | - Tugba Aydın
- Istanbul Physical Therapy Rehabilitation Training and Research Hospital, Istanbul, Turkey
| | - Ilhan Karacan
- Istanbul Physical Therapy Rehabilitation Training and Research Hospital, Istanbul, Turkey
| | - Kemal S Türker
- Physiology Department, Koç University School of Medicine, Istanbul, Turkey
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Krause A, Gollhofer A, Lee K, Freyler K, Becker T, Kurz A, Ritzmann R. Acute whole-body vibration reduces post-activation depression in the triceps surae muscle. Hum Mov Sci 2020; 72:102655. [PMID: 32721374 DOI: 10.1016/j.humov.2020.102655] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 01/09/2020] [Accepted: 06/20/2020] [Indexed: 01/22/2023]
Abstract
PURPOSE Acute whole-body vibration (WBV) is known to enhance neuromuscular activation. Especially mechanisms which act presynaptically are discussed to be involved in this modulation, but evidence is still limited. Therefore, this study aimed to investigate if 2 min of WBV might impact the premotoneuronal mechanism of post-activation depression (PAD). METHODS PAD in m. soleus was assessed by paired-pulse stimulation in 28 healthy participants prior, 2 min, 4 min and 10 min after 2 min of side-alternating WBV (10 Hz, 2 mm). Methodologies involved electromyography (m. soleus, m. tibialis anterior) and goniometric recordings (ankle, knee joint). H-reflexes were elicited with peripheral nerve stimulation and assessed by means of conditioned H-reflexes (ISI 1 s, Hcond) versus control H-reflexes (ISI10, H). RESULTS Hcond/H was significantly enhanced by +55% (2 min), +32% (4 min) and +35% (10 min) following WBV (P < 0.05). Baseline muscle activity and joint positions were shown to be reliable (Cronbach's α values >0.990) throughout the testing procedure. CONCLUSION Vibratory-induced spinal inhibition is accompanied by diminished PAD at the presynaptic terminals which interconnect the Ia afferents with the α-motoneuron. Functionally, the PAD reduction might explain enhanced motor performance following vibration therapy, but future studies will be needed to verify this assumption.
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Affiliation(s)
- Anne Krause
- Institute of Training and Computer Science in Sport, German Sport University Cologne, Germany, Am Sportpark Müngersdorf 6, 50933 Köln; Department for Sports and Sport Science, University of Freiburg, Germany, Schwarzwaldstraße 175, 79117 Freiburg i.Br
| | - Albert Gollhofer
- Department for Sports and Sport Science, University of Freiburg, Germany, Schwarzwaldstraße 175, 79117 Freiburg i.Br
| | - Kyungsoo Lee
- Department for Sports and Sport Science, University of Freiburg, Germany, Schwarzwaldstraße 175, 79117 Freiburg i.Br
| | - Kathrin Freyler
- Department for Sports and Sport Science, University of Freiburg, Germany, Schwarzwaldstraße 175, 79117 Freiburg i.Br
| | - Tobias Becker
- Department for Sports and Sport Science, University of Freiburg, Germany, Schwarzwaldstraße 175, 79117 Freiburg i.Br
| | - Alexander Kurz
- Department for Sports and Sport Science, University of Freiburg, Germany, Schwarzwaldstraße 175, 79117 Freiburg i.Br.; Bernstein Center Freiburg, University of Freiburg, Germany, Hansastraße 9a, 79104 Freiburg i.Br
| | - Ramona Ritzmann
- Department for Sports and Sport Science, University of Freiburg, Germany, Schwarzwaldstraße 175, 79117 Freiburg i.Br.; Department of Biomechanics, Rennbahnklinik, Switzerland, Kriegackerstrasse 100, 4132, Muttenz, Switzerland.
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Wiegel P, Leukel C. Training of a discrete motor skill in humans is accompanied by increased excitability of the fastest corticospinal connections at movement onset. J Physiol 2020; 598:3485-3500. [DOI: 10.1113/jp279879] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 05/21/2020] [Indexed: 11/08/2022] Open
Affiliation(s)
- Patrick Wiegel
- Department of Sport Science University of Freiburg Freiburg 79117 Germany
- Bernstein Center Freiburg University of Freiburg Freiburg 79104 Germany
| | - Christian Leukel
- Department of Sport Science University of Freiburg Freiburg 79117 Germany
- Bernstein Center Freiburg University of Freiburg Freiburg 79104 Germany
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Wiegel P, Kurz A, Leukel C. Evidence that distinct human primary motor cortex circuits control discrete and rhythmic movements. J Physiol 2020; 598:1235-1251. [PMID: 32057108 DOI: 10.1113/jp278779] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 02/10/2020] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS Discrete and rhythmic dynamics are inherent components of (human) movements. We provide evidence that distinct human motor cortex circuits contribute to discrete and rhythmic movements. Excitability of supragranular layer circuits of the human motor cortex was higher during discrete movements than during rhythmic movements. Conversely, more complex corticospinal circuits showed higher excitability during rhythmic movements than during discrete movements. No task-specific differences existed for corticospinal output neurons at infragranular layers. The excitability differences were found to be time(phase)-specific and could not be explained by the kinematic properties of the movements. The same task-specific differences were found between the last cycle of a rhythmic movement period and ongoing rhythmic movements. ABSTRACT Human actions entail discrete and rhythmic movements (DM and RM, respectively). Recent insights from human and animal studies indicate different neural control mechanisms for DM and RM, emphasizing the intrinsic nature of the task. However, how distinct human motor cortex circuits contribute to these movements remains largely unknown. In the present study, we tested distinct primary motor cortex and corticospinal circuits and proposed that they show differential excitability between DM and RM. Human subjects performed either 1) DM or 2) RM using their right wrist. We applied an advanced electrophysiological approach involving transcranial magnetic stimulation and peripheral nerve stimulation to test the excitability of the neural circuits. Probing was performed at different movement phases: movement initiation (MI, 20 ms after EMG onset) and movement execution (ME, 200 ms after EMG onset) of the wrist flexion. At MI, excitability at supragranular layers was significantly higher in DM than in RM. Conversely, excitability of more complex corticospinal circuits was significantly lower in DM than RM at ME. No task-specific differences were found for direct corticospinal output neurons at infragranular layers. The neural differences could not be explained by the kinematic properties of the movements and also existed between ongoing RM and the last cycle of RM. Our results therefore strengthen the hypothesis that different neural control mechanisms engage in DM and RM.
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Affiliation(s)
- Patrick Wiegel
- Department of Sport Science, University of Freiburg, Freiburg, 79117, Germany.,Bernstein Center Freiburg, University of Freiburg, Freiburg, 79104, Germany
| | - Alexander Kurz
- Department of Sport Science, University of Freiburg, Freiburg, 79117, Germany.,Bernstein Center Freiburg, University of Freiburg, Freiburg, 79104, Germany
| | - Christian Leukel
- Department of Sport Science, University of Freiburg, Freiburg, 79117, Germany.,Bernstein Center Freiburg, University of Freiburg, Freiburg, 79104, Germany
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Piponnier E, Ratel S, Chalchat E, Jagot K, Bontemps B, Julian V, Bocock O, Duclos M, Martin V. Plantar flexor muscle-tendon unit length and stiffness do not influence neuromuscular fatigue in boys and men. Eur J Appl Physiol 2020; 120:653-664. [DOI: 10.1007/s00421-020-04305-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 01/13/2020] [Indexed: 10/25/2022]
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Novel human models for elucidating mechanisms of rate-sensitive H-reflex depression. Biomed J 2020; 43:44-52. [PMID: 32200955 PMCID: PMC7090317 DOI: 10.1016/j.bj.2019.07.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 01/24/2019] [Accepted: 07/10/2019] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND This study used novel human neurophysiologic models to investigate whether the mechanism of rate-sensitive H-reflex depression lies in the pre-synaptic or post-synaptic locus in humans. We hypothesized that pre-synaptic inhibition would suppress Ia afferents and H-reflexes without suppressing alpha motor neurons or motor evoked potentials (MEPs). In contrast, post-synaptic inhibition would suppress alpha motor neurons, thereby reducing H-reflexes and MEPs. METHODS We recruited 23 healthy adults with typical rate-sensitive H-reflex depression, 2 participants with acute sensory-impaired spinal cord injury (SCI) (to rule out influence of sensory stimulation on supra-spinal excitability), and an atypical cohort of 5 healthy adults without rate-sensitive depression. After a single electrical stimulation to the tibial nerve, we administered either a testing H-reflex or a testing MEP at 50-5000 ms intervals. RESULTS Testing MEPs were not diminished in healthy subjects with or without typical rate-sensitive H-reflex depression, or in subjects with sensory-impaired SCI. MEP responses were similar in healthy subjects with versus without rate-sensitive H-reflex depression. CONCLUSIONS Results from these novel in vivo human models support a pre-synaptic locus of rate-sensitive H-reflex depression for the first time in humans. Spinal reflex excitability can be modulated separately from descending corticospinal influence. Each represents a potential target for neuromodulatory intervention.
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Mesquita RNO, Cronin NJ, Kyröläinen H, Hintikka J, Avela J. Effects of caffeine on neuromuscular function in a non-fatigued state and during fatiguing exercise. Exp Physiol 2020; 105:690-706. [PMID: 32092208 DOI: 10.1113/ep088265] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 01/27/2020] [Indexed: 12/22/2022]
Abstract
NEW FINDINGS What is the central question of the study? What are the effects of caffeine on neuromuscular function in a non-fatigued state and during fatiguing exercise? What is the main finding and its importance? In a non-fatigued state, caffeine decreased the duration of the silent period evoked by transcranial magnetic stimulation. Caffeine-induced reduction of inhibitory mechanisms in the central nervous system before exercise was associated with an increased performance. Individuals who benefit from caffeine ingestion may experience lower perception of effort during exercise and an accelerated recovery of M-wave amplitude postfatigue. This study elucidates the mechanisms of action of caffeine and demonstrates that inter-individual variability of its effects on neuromuscular function is a fruitful area for further work. ABSTRACT Caffeine enhances exercise performance, but its mechanisms of action remain unclear. In this study, we investigated its effects on neuromuscular function in a non-fatigued state and during fatiguing exercise. Eighteen men participated in this randomized, double-blind, placebo-controlled crossover trial. Baseline measures included plantarflexion force, drop jump, squat jump, voluntary activation of triceps surae muscle, soleus muscle contractile properties, M-wave, α-motoneuron excitability (H-reflex), corticospinal excitability, short-interval intracortical inhibition, intracortical facilitation, silent period evoked by transcranial magnetic stimulation (SP) and plasma potassium and caffeine concentrations. Immediately after baseline testing, participants ingested caffeine (6 mg·kg-1 ) or placebo. After a 1-h rest, baseline measures were repeated, followed by a fatiguing stretch-shortening cycle exercise (sets of 40 bilateral rebound jumps on a sledge apparatus) until task failure. Neuromuscular testing was carried out throughout the fatigue protocol and afterwards. Caffeine enhanced drop jump height (by 4.2%) and decreased the SP (by 12.6%) in a non-fatigued state. A caffeine-related decrease in SP and short-interval intracortical inhibition before the fatiguing activity was associated with an increased time to task failure. The participants who benefitted from an improved performance on the caffeine day reported a significantly lower sense of effort during exercise and had an accelerated postexercise recovery of M-wave amplitude. Caffeine modulates inhibitory mechanisms of the CNS, recovery of M-wave amplitude and perception of effort. This study lays the groundwork for future examinations of differences in caffeine-induced neuromuscular changes between those who are deemed to benefit from caffeine ingestion and those who are not.
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Affiliation(s)
- Ricardo N O Mesquita
- School of Medical and Health Sciences, Edith Cowan University, Perth, WA, Australia.,Neuromuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Neil J Cronin
- Neuromuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland.,Department for Health, Bath University, Bath, UK
| | - Heikki Kyröläinen
- Neuromuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Jukka Hintikka
- Neuromuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Janne Avela
- Neuromuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
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Effect of Ankle Angles on the Soleus H-Reflex Excitability During Standing. Motor Control 2020; 24:189-203. [PMID: 31899887 DOI: 10.1123/mc.2018-0118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 10/24/2019] [Accepted: 10/29/2019] [Indexed: 11/18/2022]
Abstract
This study investigated effects of ankle joint angle on the Hoffman's reflex (H-reflex) excitability during loaded (weight borne with both legs) and unloaded (full body weight borne with the contralateral leg) standing in people without neurological injuries. Soleus H-reflex/M-wave recruitment curves were examined during upright standing on three different slopes that imposed plantar flexion (-15°), dorsiflexion (+15°), and neutral (0°) angles at the ankle, with the test leg loaded and unloaded. With the leg loaded and unloaded, maximum H-reflex/maximum M-wave ratio of -15° was significantly larger than those of 0° and +15° conditions. The maximum H-reflex/maximum M-wave ratios were 51%, 43%, and 41% with loaded and 56%, 46%, and 44% with unloaded for -15°, 0°, and +15° slope conditions, respectively. Thus, limb loading/unloading had limited impact on the extent of influence that ankle angles exert on the H-reflex excitability. This suggests that task-dependent central nervous system control of reflex excitability may regulate the influence of sensory input on the spinal reflex during standing.
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Hofstoetter US, Freundl B, Binder H, Minassian K. Recovery cycles of posterior root-muscle reflexes evoked by transcutaneous spinal cord stimulation and of the H reflex in individuals with intact and injured spinal cord. PLoS One 2019; 14:e0227057. [PMID: 31877192 PMCID: PMC6932776 DOI: 10.1371/journal.pone.0227057] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 12/10/2019] [Indexed: 11/18/2022] Open
Abstract
Posterior root-muscle (PRM) reflexes are short-latency spinal reflexes evoked by epidural or transcutaneous spinal cord stimulation (SCS) in clinical and physiological studies. PRM reflexes share key physiological characteristics with the H reflex elicited by electrical stimulation of large-diameter muscle spindle afferents in the tibial nerve. Here, we compared the H reflex and the PRM reflex of soleus in response to transcutaneous stimulation by studying their recovery cycles in ten neurologically intact volunteers and ten individuals with traumatic, chronic spinal cord injury (SCI). The recovery cycles of the reflexes, i.e., the time course of their excitability changes, were assessed by paired pulses with conditioning-test intervals of 20–5000 ms. Between the subject groups, no statistical difference was found for the recovery cycles of the H reflexes, yet those of the PRM reflexes differed significantly, with a striking suppression in the intact group. When comparing the reflex types, they did not differ in the SCI group, while the PRM reflexes were more strongly depressed in the intact group for durations characteristic for presynaptic inhibition. These differences may arise from the concomitant stimulation of several posterior roots containing afferent fibers of various lower extremity nerves by transcutaneous SCS, producing multi-source heteronymous presynaptic inhibition, and the collective dysfunction of inhibitory mechanisms after SCI contributing to spasticity. PRM-reflex recovery cycles additionally obtained for bilateral rectus femoris, biceps femoris, tibialis anterior, and soleus all demonstrated a stronger suppression in the intact group. Within both subject groups, the thigh muscles showed a stronger recovery than the lower leg muscles, which may reflect a characteristic difference in motor control of diverse muscles. Based on the substantial difference between intact and SCI individuals, PRM-reflex depression tested with paired pulses could become a sensitive measure for spasticity and motor recovery.
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Affiliation(s)
- Ursula S. Hofstoetter
- Center for Medical Physics and Biomedical Engineering, Medical University Vienna, Vienna, Austria
- * E-mail:
| | - Brigitta Freundl
- Neurological Center, Maria Theresien Schloessel, Otto Wagner Hospital, Vienna, Austria
| | - Heinrich Binder
- Neurological Center, Maria Theresien Schloessel, Otto Wagner Hospital, Vienna, Austria
| | - Karen Minassian
- Center for Medical Physics and Biomedical Engineering, Medical University Vienna, Vienna, Austria
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Repeated transspinal stimulation decreases soleus H-reflex excitability and restores spinal inhibition in human spinal cord injury. PLoS One 2019; 14:e0223135. [PMID: 31557238 PMCID: PMC6762874 DOI: 10.1371/journal.pone.0223135] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 09/14/2019] [Indexed: 12/12/2022] Open
Abstract
Transcutaneous spinal cord or transspinal stimulation over the thoracolumbar enlargement, the spinal location of motoneurons innervating leg muscles, modulates neural circuits engaged in the control of movement. The extent to which daily sessions (e.g. repeated) of transspinal stimulation affects soleus H-reflex excitability in individuals with chronic spinal cord injury (SCI) remains largely unknown. In this study, we established the effects of repeated cathodal transspinal stimulation on soleus H-reflex excitability and spinal inhibition in individuals with and without chronic SCI. Ten SCI and 10 healthy control subjects received monophasic transspinal stimuli of 1-ms duration at 0.2 Hz at subthreshold and suprathreshold intensities of the right soleus transspinal evoked potential (TEP). SCI subjects received an average of 16 stimulation sessions, while healthy control subjects received an average of 10 stimulation sessions. Before and one or two days post intervention, we used the soleus H reflex to assess changes in motoneuron recruitment, homosynaptic depression following single tibial nerve stimuli delivered at 0.1, 0.125, 0.2, 0.33 and 1.0 Hz, and postactivation depression following paired tibial nerve stimuli at the interstimulus intervals of 60, 100, 300, and 500 ms. Soleus H-reflex excitability was decreased in both legs in motor incomplete and complete SCI but not in healthy control subjects. Soleus H-reflex homosynaptic and postactivation depression was present in motor incomplete and complete SCI but was of lesser strength to that observed in healthy control subjects. Repeated transspinal stimulation increased homosynaptic depression in all SCI subjects and remained unaltered in healthy controls. Postactivation depression remained unaltered in all subject groups. Lastly, transspinal stimulation decreased the severity of spasms and ankle clonus. The results indicate decreased reflex hyperexcitability and recovery of spinal inhibitory control in the injured human spinal cord with repeated transspinal stimulation. Transspinal stimulation is a noninvasive neuromodulation method for restoring spinally-mediated afferent reflex actions after SCI in humans.
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Hofstoetter US, Freundl B, Danner SM, Krenn MJ, Mayr W, Binder H, Minassian K. Transcutaneous Spinal Cord Stimulation Induces Temporary Attenuation of Spasticity in Individuals with Spinal Cord Injury. J Neurotrauma 2019; 37:481-493. [PMID: 31333064 DOI: 10.1089/neu.2019.6588] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Epidural spinal cord stimulation (SCS) is currently regarded as a breakthrough procedure for enabling movement after spinal cord injury (SCI), yet one of its original applications was for spinal spasticity. An emergent method that activates similar target neural structures non-invasively is transcutaneous SCS. Its clinical value for spasticity control would depend on inducing carry-over effects, because the surface-electrode-based approach cannot be applied chronically. We evaluated single-session effects of transcutaneous lumbar SCS in 12 individuals with SCI by a test-battery approach, before, immediately after and 2 h after intervention. Stimulation was applied for 30 min at 50 Hz with an intensity sub-threshold for eliciting reflexes in lower extremity muscles. The tests included evaluations of stretch-induced spasticity (Modified Ashworth Scale [MAS] sum score, pendulum test, electromyography-based evaluation of tonic stretch reflexes), clonus, cutaneous-input-evoked spasms, and the timed 10 m walk test. Across participants, the MAS sum score, clonus, and spasms were significantly reduced immediately after SCS, and all spasticity measures were improved 2 h post-intervention, with large effect sizes and including clinically meaningful improvements. The effect on walking speed varied across individuals. We further conducted a single-case multi-session study over 6 weeks to explore the applicability of transcutaneous SCS as a home-based therapy. Self-application of the intervention was successful; weekly evaluations suggested progressively improving therapeutic effects during the active period and carry-over effects for 7 days. Our results suggest that transcutaneous SCS can be a viable non-pharmacological option for managing spasticity, likely working through enhancing pre- and post-synaptic spinal inhibitory mechanisms, and may additionally serve to identify responders to treatments with epidural SCS.
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Affiliation(s)
- Ursula S Hofstoetter
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Brigitta Freundl
- Neurological Center, SMZ Baumgartner Hoehe, Otto-Wagner-Hospital, Vienna, Austria
| | - Simon M Danner
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Matthias J Krenn
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi.,Center for Neuroscience and Neurological Recovery, Methodist Rehabilitation Center, Jackson, Mississippi
| | - Winfried Mayr
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Heinrich Binder
- Neurological Center, SMZ Baumgartner Hoehe, Otto-Wagner-Hospital, Vienna, Austria
| | - Karen Minassian
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
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Kinnunen JV, Piitulainen H, Piirainen JM. Neuromuscular Adaptations to Short-Term High-Intensity Interval Training in Female Ice-Hockey Players. J Strength Cond Res 2019; 33:479-485. [PMID: 28277422 DOI: 10.1519/jsc.0000000000001881] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Kinnunen, J-V, Piitulainen, H, and Piirainen, JM. Neuromuscular adaptations to short-term high-intensity interval training in female ice-hockey players. J Strength Cond Res 33(2): 479-485, 2019-High-intensity interval training (HIIT)-related neuromuscular adaptations, changes in force production, and on-ice performance were investigated in female ice-hockey players during preseason. Fourteen Finnish championship level ice-hockey players (average age 22 ± 3 years) participated in 2½-week HIIT. Both spinal (H-reflex) and supraspinal (V-wave) neuromuscular responses of the soleus muscle were recorded before and after the training period. Static jump (SJ) and countermovement jump heights, plantarflexor maximum voluntary contraction (MVC), and rate of force development (RFD) were measured. In addition, soleus and tibialis anterior muscle activations (electromyography) were measured during MVC and RFD tests. During on-ice training, skating speed and acceleration tests were performed. Subjects significantly improved their plantarflexion MVC force (11.6 ± 11.2%, p < 0.001), RFD (15.2 ± 15.9%, p < 0.01), and SJ (4.8 ± 7.6%, p ≤ 0.05). Voluntary motor drive to the soleus muscle (V-wave amplitude) increased by 16.0 ± 15.4% (p < 0.01), and coactivation of the tibialis anterior muscle during the plantarflexion RFD test was reduced by -18.9 ± 22.2% (p ≤ 0.05). No change was observed in spinal α-motoneuron excitability (H-reflex) during MVC or in on-ice performance. These results indicate that HIIT can be used to improve athletes' capability to produce maximal and explosive forces, likely through enhanced voluntary activation of their muscles and reduced antagonist coactivation. Therefore, HIIT can be recommended in preseason training to improve neuromuscular performance. However, a longer than 2½-week HIIT period is needed to improve on-ice performance in female ice-hockey players.
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Affiliation(s)
- Juho-Ville Kinnunen
- Neuromuscular Research Center, Unit of Biology of Physical Activity, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä Finland
| | - Harri Piitulainen
- Department of Neuroscience and Biomedical Engineering, School of Science, Aalto University, Helsinki, Finland
| | - Jarmo M Piirainen
- Neuromuscular Research Center, Unit of Biology of Physical Activity, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä Finland
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Wallace BJ, Shapiro R, Wallace KL, Abel MG, Symons TB. Muscular and Neural Contributions to Postactivation Potentiation. J Strength Cond Res 2019; 33:615-625. [PMID: 30589723 DOI: 10.1519/jsc.0000000000003011] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Wallace, BJ, Shapiro, R, Wallace, KL, Abel, MG, and Symons, TB. Muscular and neural contributions to postactivation potentiation. J Strength Cond Res 33(3): 615-625, 2019-This study's purpose was to explain the relationship between muscle factors (twitch potentiation [TP]) and neural factors (reflex potentiation) contributing to total postactivation potentiation (PAP) that couples these. The tibial nerve of 15 participants were stimulated intermittently for 20 minutes at supramaximal (Mmax) and submaximal (Hmax) intensities on separate days under 2 conditions: (a) rest (Control) and (b) after a 10-second plantarflexion maximum voluntary isometric contraction (MVIC). Isometric twitch torque and rate of force development (RFD) as well as soleus and gastrocnemius electromyographic values were analyzed. Torque and RFD TP were significantly greater 10 and 30 seconds after MVIC vs. Control. Postactivation potentiation of torque and RFD at Hmax were highest at 3 and 4.5 minutes after MVIC, respectively, with RFD significantly elevated. Electromyographic values were not different between conditions. Twitch potentiation significantly contributed to PAP at the following time points: 20 seconds, Hmax peak, and 20 minutes after MVIC (torque: R = 0.54, 0.76, and 0.70; RFD: R = 0.46, 0.59, and 0.53). The soleus significantly contributed to PAP torque at 20 seconds and 20 minutes after MVIC, and to PAP RFD at 20 seconds, 4.5 minutes, and 20 minutes (torque: R = 0.26 and 0.34, p ≤ 0.05; RFD: R = 0.65, 0.52, and 0.41). The gastrocnemius did not significantly contribute to PAP. Both muscle and neural factors play a significant role in PAP, and neural factors may play a more prominent role in RFD potentiation than torque potentiation.
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Affiliation(s)
- Brian J Wallace
- Department of Kinesiology, University of Wisconsin Oshkosh, Oshkosh, Wisconsin
| | - Robert Shapiro
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, Kentucky
| | - Kelly L Wallace
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, Kentucky
| | - Mark G Abel
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, Kentucky
| | - Thorburn B Symons
- Department of Health and Sport Sciences, University of Louisville, Louisville, Kentucky
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Oza PD, Dudley-Javoroski S, Shields RK. Sustained submaximal contraction yields biphasic modulation of soleus Post-activation depression in healthy humans. Scand J Med Sci Sports 2019; 29:944-951. [PMID: 30892718 DOI: 10.1111/sms.13421] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 02/01/2019] [Accepted: 03/14/2019] [Indexed: 12/23/2022]
Abstract
The amplitude of the H-reflex during the development and progression of fatigue reflects a complex interplay between central and peripheral factors. The purpose of this study is to characterize H-reflex homosynaptic post-activation depression (PAD) in an online fashion during a sustained submaximal fatigue task. The task required a high motor output in order to increase the likelihood of creating partial muscle ischemia with accumulation of fatigue metabolites, an important potential inhibitory influence upon the H-reflex during the progression of fatigue. Eleven subjects without neurologic impairment maintained volitional, isometric plantar flexion at 60% of maximal voluntary contraction until exhaustion. A paired-pulse stimulus (2 Hz) was delivered to the tibial nerve to elicit paired H-reflexes before, during, and after the fatigue protocol. The normalized amplitude of the second H-reflex (depression ratio) served as an estimate of PAD. Depression ratio increased during the first half of the fatigue protocol (P < 0.001), indicating a diminution of PAD, and then returned as exhaustion approached. The biphasic behavior of homosynaptic H-reflex depression during fatigue to exhaustion suggests a role for metabolic mediators of post-activation depression during fatigue.
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Affiliation(s)
- Preeti D Oza
- Department of Physical Therapy, University of the Pacific, Stockton, California
| | - Shauna Dudley-Javoroski
- Department of Physical Therapy Rehabilitation Science, Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, Iowa
| | - Richard K Shields
- Department of Physical Therapy Rehabilitation Science, Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, Iowa
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Quilgars C, Bertrand SS. Activity-dependent synaptic dynamics in motor circuits of the spinal cord. CURRENT OPINION IN PHYSIOLOGY 2019. [DOI: 10.1016/j.cophys.2018.12.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Toossi A, Everaert DG, Uwiera RRE, Hu DS, Robinson K, Gragasin FS, Mushahwar VK. Effect of anesthesia on motor responses evoked by spinal neural prostheses during intraoperative procedures. J Neural Eng 2019; 16:036003. [PMID: 30790787 DOI: 10.1088/1741-2552/ab0938] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVE The overall goal of this study was to investigate the effects of various anesthetic protocols on the intraoperative responses to intraspinal microstimulation (ISMS). ISMS is a neuroprosthetic approach that targets the motor networks in the ventral horns of the spinal cord to restore function after spinal cord injury. In preclinical studies, ISMS in the lumbosacral enlargement produced standing and walking by activating networks controlling the hindlimb muscles. ISMS implants are placed surgically under anesthesia, and refinements in placement are made based on the evoked responses. Anesthesia can have a significant effect on the responses evoked by spinal neuroprostheses; therefore, in preparation for clinical testing of ISMS, we compared the evoked responses under a common clinical neurosurgical anesthetic protocol with those evoked under protocols commonly used in preclinical studies. APPROACH Experiments were conducted in seven pigs. An ISMS microelectrode array was implanted in the lumbar enlargement and responses to ISMS were measured under three anesthetic protocols: (1) isoflurane, an agent used pre-clinically and clinically, (2) total intravenous anesthesia (TIVA) with propofol as the main agent commonly used in clinical neurosurgical procedures, (3) TIVA with sodium pentobarbital, an anesthetic agent used mostly preclinically. Responses to ISMS were evaluated based on stimulation thresholds, movement kinematics, and joint torques. Motor evoked potentials (MEP) and plasma concentrations of propofol were also measured. MAIN RESULTS ISMS under propofol anesthesia produced large and functional responses that were not statistically different from those produced under pentobarbital anesthesia. Isoflurane, however, significantly suppressed the ISMS-evoked responses. SIGNIFICANCE This study demonstrated that the choice of anesthesia is critical for intraoperative assessments of motor responses evoked by spinal neuroprostheses. Propofol and pentobarbital anesthesia did not overly suppress the effects of ISMS; therefore, propofol is expected to be a suitable anesthetic agent for clinical intraoperative testing of an intraspinal neuroprosthetic system.
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Affiliation(s)
- Amirali Toossi
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada. Sensory Motor Adaptive Rehabilitative Technology (SMART) Network, University of Alberta, Edmonton, AB, Canada
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