scholarly journals Increase in reciprocal Ia inhibition during antagonist contraction in the human leg: a study of motor units and the H reflex.

1995 ◽  
Vol 489 (1) ◽  
pp. 275-285 ◽  
Author(s):  
M Shindo ◽  
S Yanagawa ◽  
H Morita ◽  
N Yanagisawa
Keyword(s):  
Motor Units ◽  
H Reflex ◽  
Ia Inhibition

Interlimb coupling from the arms to legs is differentially specified for populations of motor units comprising the compound H-reflex during “reduced” human locomotion

2010 ◽  
Vol 208 (2) ◽  
pp. 157-168 ◽  
Author(s):  
Rinaldo A. Mezzarane ◽  
Marc Klimstra ◽  
Allen Lewis ◽  
Sandra R. Hundza ◽  
E. Paul Zehr
Keyword(s):  
Motor Units ◽  
Human Locomotion ◽  
H Reflex ◽  
Interlimb Coupling

Change in motoneuronal population in H-reflex, studied by firing probability of motor units in man

1989 ◽  
Vol 9 ◽  
pp. 86
Author(s):  
Masaomi Shindo ◽  
Takao Hashimoto ◽  
Sohei Yanagawa ◽  
Nobuo Yanagisawa ◽  
Reisaku Tanaka
Keyword(s):  
Motor Units ◽  
H Reflex

Muscle Spindle Afferent Input to Motoneurons in Human Masseter

1999 ◽  
Vol 82 (1) ◽  
pp. 505-507 ◽  
Author(s):  
Sheila D. Scutter ◽  
Kemal S. Türker
Keyword(s):  
Muscle Spindle ◽  
Motor Units ◽  
Afferent Input ◽  
H Reflex ◽  
Skewed Distribution ◽  
Reflex Response ◽  
Muscle Spindle Afferents ◽  
Single Motor ◽  
Single Motor Units ◽  
Inhibitory Mechanisms

The H-reflex response in large and small single motor units in human deep anterior masseter was studied to investigate the distribution of muscle spindle afferents onto masseter motoneurons. We found that only the larger units displayed H-reflex responses. This indicates preferential distribution of muscle spindle input onto large motoneurons or a skewed distribution of tonic presynaptic inhibitory mechanisms.

Heteronymous H-reflex in Temporal Muscle Motor Units

1998 ◽  
Vol 77 (12) ◽  
pp. 1960-1964 ◽  
Author(s):  
G.M. Macaluso ◽  
G. Pavesi ◽  
A. De Laat
Keyword(s):  
Motor Units ◽  
H Reflex ◽  
Temporal Muscle

scholarly journals Effect of ageing on the electrical and mechanical properties of human soleus motor units activated by the H reflex and M wave

2003 ◽  
Vol 548 (2) ◽  
pp. 649-661 ◽  
Author(s):  
G Scaglioni ◽  
M V Narici ◽  
N A Maffiuletti ◽  
M Pensini ◽  
A Martin
Keyword(s):  
Mechanical Properties ◽  
Motor Units ◽  
H Reflex ◽  
M Wave

The relative contribution to the plantar-flexor torque of the soleus motor units activated by the H reflex and M response in humans

2000 ◽  
Vol 288 (2) ◽  
pp. 127-130 ◽  
Author(s):  
Nicola A Maffiuletti ◽  
Alain Martin ◽  
Jacques Van Hoecke ◽  
Marco Schieppati
Keyword(s):  
Motor Units ◽  
H Reflex ◽  
Plantar Flexor ◽  
Relative Contribution

scholarly journals Paired Associative Stimulation Induces Change in Presynaptic Inhibition of Ia Terminals in Wrist Flexors in Humans

2010 ◽  
Vol 104 (2) ◽  
pp. 755-764 ◽  
Author(s):  
Jean-Charles Lamy ◽  
Heike Russmann ◽  
Ejaz A. Shamim ◽  
Sabine Meunier ◽  
Mark Hallett
Keyword(s):  
Presynaptic Inhibition ◽  
Motor Evoked Potentials ◽  
Long Term Potentiation ◽  
H Reflex ◽  
Paired Associative Stimulation ◽  
Before And After ◽  
Ia Inhibition ◽  
Cortical Synapses ◽  
Postactivation Depression ◽  
Spinal Excitability

Enhancements in the strength of corticospinal projections to muscles are induced in conscious humans by paired associative stimulation (PAS) to the motor cortex. Although most of the previous studies support the hypothesis that the increase of the amplitude of motor evoked potentials (MEPs) by PAS involves long-term potentiation (LTP)-like mechanism in cortical synapses, changes in spinal excitability after PAS have been reported, suggestive of parallel modifications in both cortical and spinal excitability. In a first series of experiments ( experiment 1), we confirmed that both flexor carpi radialis (FCR) MEPs and FCR H reflex recruitment curves are enhanced by PAS. To elucidate the mechanism responsible for this change in the H reflex amplitude, we tested, using the same subjects, the hypothesis that enhanced H reflexes are caused by a down-regulation of the efficacy of mechanisms controlling Ia afferent discharge, including presynaptic Ia inhibition and postactivation depression. To address this question, amounts of both presynaptic Ia inhibition of FCR Ia terminals (D1and D2 inhibitions methods; experiment 2) and postactivation depression ( experiment 3) were determined before and after PAS. Results showed that PAS induces a significant decrease of presynaptic Ia inhibition of FCR terminals, which was concomitant with the facilitation of the H reflex. Postactivation depression was unaffected by PAS. It is argued that enhancement of segmental excitation by PAS relies on a selective effect of PAS on the interneurons controlling presynaptic inhibition of Ia terminals.

Therapeutic Elastic Tapes Applied in Different Directions Over the Triceps Surae Do Not Modulate Reflex Excitability of the Soleus Muscle

2021 ◽  
Vol 30 (1) ◽  
pp. 22-29
Author(s):  
Igor E.J. Magalhães ◽  
Rinaldo A. Mezzarane ◽  
Rodrigo L. Carregaro
Keyword(s):  
Subcutaneous Tissue ◽  
Motor Units ◽  
H Reflex ◽  
Triceps Surae ◽  
Physically Active ◽  
Recruitment Curve ◽  
Muscle Insertion ◽  
Electrophysiological Responses ◽  
Within Subjects ◽  
Underlying Mechanisms

Context: Elastic taping has been widely used for either to facilitate or to inhibit muscle contraction. The efficacy of elastic taping is allegedly ascribed to physiological mechanisms related to subcutaneous tissue and muscle stimulation as a result of tape tension and direction. However, the underlying mechanisms that support the use of elastic taping are still unclear. Objective: To investigate changes in electrophysiological responses after 48 hours of tape application in different directions on the calf muscles of healthy individuals. Design: Within-subjects design. Setting: Research laboratory. Participants: Twenty-seven physically active males (age 18.0 [4.2] y, height 1.65 [0.07] m, body mass 62.3 [10.3] kg) participated. Interventions: Soleus H-reflex responses were evoked through stimulation of the tibial posterior nerve with 2- to 4-second interval between stimuli (32 sweeps) for each condition (baseline: without tape; facilitation: tape applied from muscle origin to insertion; inhibition: tape applied from muscle insertion to origin). Main Outcome Measures: The H-reflex amplitude values were normalized by the maximal direct response (Mmax). Parameters were estimated from a sigmoidal fit of the H-reflex recruitment curve (ascending limb). Results: No significant differences were found for the parameters derived from the recruitment curve of the H-reflex among the conditions (P > .05). Conclusions: The authors’ findings showed that, irrespective of the direction of tape application, the elastic tape applied over the triceps surae does not generate any significant alteration on the excitability of the reflex pathway for different subpopulations of motor units. The authors therefore suggest a re-examination of the current recommendations on taping direction in clinical and sports activities.

Modulation of H Reflex of Pretibial Muscles and Reciprocal Ia Inhibition of Soleus Muscle During Voluntary Teeth Clenching in Humans

2000 ◽  
Vol 83 (4) ◽  
pp. 2063-2070 ◽  
Author(s):  
Yoshiyuki Takada ◽  
Takao Miyahara ◽  
Tatsuya Tanaka ◽  
Takashi Ohyama ◽  
Yoshio Nakamura
Keyword(s):  
Soleus Muscle ◽  
Peroneal Nerve ◽  
Common Peroneal Nerve ◽  
H Reflex ◽  
Electromyographic Activity ◽  
Dependent Manner ◽  
Teeth Clenching ◽  
Ia Inhibition ◽  
The Common ◽  
Stimulation Of

A previous study has demonstrated that the soleus H reflex is facilitated in association with voluntary teeth clenching in proportion with biting force in humans. The present study tried to elucidate the functional significance of this facilitation of the soleus H reflex, by examining 1) whether the facilitation of the H reflex is reciprocal or nonreciprocal between the ankle extensors and flexors and 2) whether the reciprocal Ia inhibition of crural muscles is facilitated or depressed in association with voluntary teeth clenching. The H reflex of the pretibial muscles was evoked by stimulation of the common peroneal nerve in seven healthy subjects with no oral dysfunction. The pretibial H reflex was facilitated in association with voluntary teeth clenching in a force-dependent manner. The facilitation started preceding the onset of electromyographic activity of the masseter muscle. Stimulation of the common peroneal nerve at low intensities subthreshold for evoking the M wave of the pretibial muscles inhibited the soleus H reflex after a short latency corresponding with a disynaptic inhibition, indicating that the reciprocal Ia inhibition was depressed in association with voluntary teeth clenching. Thus, the present study has shown that voluntary teeth clenching evokes a nonreciprocal facilitation of ankle extensor and flexor muscles and attenuated reciprocal Ia inhibition from the pretibial muscles to the soleus muscle. It is concluded that voluntary teeth clenching contributes to improve stability of stance rather than smoothness of movements.

scholarly journals Physiological recruitment of motor units by high-frequency electrical stimulation of afferent pathways

2015 ◽  
Vol 118 (3) ◽  
pp. 365-376 ◽  
Author(s):  
Jakob L. Dideriksen ◽  
Silvia Muceli ◽  
Strahinja Dosen ◽  
Christopher M. Laine ◽  
Dario Farina
Keyword(s):  
Electrical Stimulation ◽  
Motor Unit ◽  
High Frequency ◽  
Muscle Activation ◽  
Motor Units ◽  
H Reflex ◽  
Motor Unit Recruitment ◽  
Afferent Stimulation ◽  
Reflex Responses ◽  
Stimulation Of

Neuromuscular electrical stimulation (NMES) is commonly used in rehabilitation, but electrically evoked muscle activation is in several ways different from voluntary muscle contractions. These differences lead to challenges in the use of NMES for restoring muscle function. We investigated the use of low-current, high-frequency nerve stimulation to activate the muscle via the spinal motoneuron (MN) pool to achieve more natural activation patterns. Using a novel stimulation protocol, the H-reflex responses to individual stimuli in a train of stimulation pulses at 100 Hz were reliably estimated with surface EMG during low-level contractions. Furthermore, single motor unit recruitment by afferent stimulation was analyzed with intramuscular EMG. The results showed that substantially elevated H-reflex responses were obtained during 100-Hz stimulation with respect to a lower stimulation frequency. Furthermore, motor unit recruitment using 100-Hz stimulation was not fully synchronized, as it occurs in classic NMES, and the discharge rates differed among motor units because each unit was activated only after a specific number of stimuli. The most likely mechanism behind these observations is the temporal summation of subthreshold excitatory postsynaptic potentials from Ia fibers to the MNs. These findings and their interpretation were also verified by a realistic simulation model of afferent stimulation of a MN population. These results suggest that the proposed stimulation strategy may allow generation of considerable levels of muscle activation by motor unit recruitment that resembles the physiological conditions.

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