scholarly journals Enhancement of Arm and Leg Locomotor Coupling With Augmented Cutaneous Feedback From the Hand

2007 ◽  
Vol 98 (3) ◽  
pp. 1810-1814 ◽  
Author(s):  
E. Paul Zehr ◽  
Marc Klimstra ◽  
Katie Dragert ◽  
Yasaman Barzi ◽  
Mark G. Bowden ◽  
...  
Keyword(s):  
Significant Contribution ◽  
Movement Control ◽  
Suppressive Effect ◽  
Cycle Ergometer ◽  
H Reflex ◽  
Reflex Amplitude ◽  
Cutaneous Feedback ◽  
Leg Cycling ◽  
Leg Movement ◽  
Stimulation Of

Cutaneous feedback from the hand could assist with coordination between the arms and legs during locomotion. Previously we used a reduced walking model of combined arm and leg (arm&leg) cycling to examine the separate effects of rhythmic arm (arm) and leg (leg) movement. Here we use this same paradigm to test the modulation H-reflexes with and without interlimb cutaneous conditioning evoked by stimulating a nerve innervating the hand (superficial radial, SR). It was hypothesized that both arm and leg would contribute significantly to suppression of H-reflex amplitude during arm&leg. We also predicted a conservation of interlimb cutaneous conditioning during movement and an interaction between arm and leg rhythmic movement control. Subjects were seated in a recumbent arm&leg cycle ergometer and maintained a low-level soleus contraction for all tasks. H-reflex amplitude was facilitated by cutaneous conditioning evoked by stimulation of the SR nerve. H-reflex amplitudes were taken from recruitment curves and included modulation of 50% Hmax and Hmax. The suppressive effect of arm was less than that for leg and arm&leg, while suppression during leg and arm&leg were generally equivalent. For H-reflexes conditioned by cutaneous input, amplitudes during arm&leg instead were in between those for arm and leg modulation. Multiple regression analysis revealed a significant contribution for arm only in trials when SR stimulation was used to condition H-reflex amplitudes. We suggest that there is a measurable interaction between neural activity regulating arm and leg movement during locomotion that is specifically enhanced when cutaneous input from the hand is present.

Robotic-assisted stepping modulates monosynaptic reflexes in forearm muscles in the human

2011 ◽  
Vol 106 (4) ◽  
pp. 1679-1687 ◽  
Author(s):  
Tsuyoshi Nakajima ◽  
Taku Kitamura ◽  
Kiyotaka Kamibayashi ◽  
Tomoyoshi Komiyama ◽  
E. Paul Zehr ◽  
...  
Keyword(s):  
Suppressive Effect ◽  
H Reflex ◽  
Afferent Feedback ◽  
Quiet Standing ◽  
Reflex Amplitude ◽  
Robotic Assisted ◽  
Forelimb Muscles ◽  
Leg Movement ◽  
Gait Trainer ◽  
Body Loading

Although the amplitude of the Hoffmann (H)-reflex in the forelimb muscles is known to be suppressed during rhythmic leg movement, it is unknown which factor plays a more important role in generating this suppression—movement-related afferent feedback or feedback related to body loading. To specifically explore the movement- and load-related afferent feedback, we investigated the modulation of the H-reflex in the flexor carpi radialis (FCR) muscle during robotic-assisted passive leg stepping. Passive stepping and standing were performed using a robotic gait-trainer system (Lokomat). The H-reflex in the FCR, elicited by electrical stimulation to the median nerve, was recorded at 10 different phases of the stepping cycle, as well as during quiet standing. We confirmed that the magnitude of the FCR H-reflex was suppressed significantly during passive stepping compared with during standing. The suppressive effect on the FCR H-reflex amplitude was seen at all phases of stepping, irrespective of whether the stepping was conducted with body weight loaded or unloaded. These results suggest that movement-related afferent feedback, rather than load-related afferent feedback, plays an important role in suppressing the FCR H-reflex amplitude.

scholarly journals Effect of cervicolumbar coupling on spinal reflexes during cycling after incomplete spinal cord injury

2018 ◽  
Vol 120 (6) ◽  
pp. 3172-3186 ◽  
Author(s):  
R. Zhou ◽  
B. Parhizi ◽  
J. Assh ◽  
L. Alvarado ◽  
R. Ogilvie ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
H Reflex ◽  
Spinal Reflexes ◽  
Incomplete Spinal Cord Injury ◽  
Reflex Amplitude ◽  
Arm Cycling ◽  
Cord Injury ◽  
Leg Cycling ◽  
Cycling Training

Spinal networks in the cervical and lumbar cord are actively coupled during locomotion to coordinate arm and leg activity. The goals of this project were to investigate the intersegmental cervicolumbar connectivity during cycling after incomplete spinal cord injury (iSCI) and to assess the effect of rehabilitation training on improving reflex modulation mediated by cervicolumbar pathways. Two studies were conducted. In the first, 22 neurologically intact (NI) people and 10 people with chronic iSCI were recruited. The change in H-reflex amplitude in flexor carpi radialis (FCR) during leg cycling and H-reflex amplitude in soleus (SOL) during arm cycling were investigated. In the second study, two groups of participants with chronic iSCI underwent 12 wk of cycling training: one performed combined arm and leg cycling (A&L) and the other legs only cycling (Leg). The effect of training paradigm on the amplitude of the SOL H-reflex was assessed. Significant reduction in the amplitude of both FCR and SOL H-reflexes during dynamic cycling of the opposite limbs was found in NI participants but not in participants with iSCI. Nonetheless, there was a significant reduction in the SOL H-reflex during dynamic arm cycling in iSCI participants after training. Substantial improvements in SOL H-reflex properties were found in the A&L group after training. The results demonstrate that cervicolumbar modulation during rhythmic movements is disrupted in people with chronic iSCI; however, this modulation is restored after cycling training. Furthermore, involvement of the arms simultaneously with the legs during training may better regulate the leg spinal reflexes.NEW & NOTEWORTHY This work systematically demonstrates the disruptive effect of incomplete spinal cord injury on cervicolumbar coupling during rhythmic locomotor movements. It also shows that the impaired cervicolumbar coupling could be significantly restored after cycling training. Actively engaging the arms in rehabilitation paradigms for the improvement of walking substantially regulates the excitability of the lumbar spinal networks. The resulting regulation may be better than that obtained by interventions that focus on training of the legs only.

Rhythmic leg cycling modulates forearm muscle H-reflex amplitude and corticospinal tract excitability

2007 ◽  
Vol 419 (1) ◽  
pp. 10-14 ◽  
Author(s):  
E. Paul Zehr ◽  
Marc Klimstra ◽  
Elizabeth A. Johnson ◽  
Timothy J. Carroll
Keyword(s):  
Corticospinal Tract ◽  
H Reflex ◽  
Reflex Amplitude ◽  
Leg Cycling ◽  
Forearm Muscle

scholarly journals Simultaneous Cervical and Lumbar Spinal Cord Stimulation Induces Facilitation of Both Spinal and Corticospinal Circuitry in Humans

2021 ◽  
Vol 15 ◽  
Author(s):  
Behdad Parhizi ◽  
Trevor S. Barss ◽  
Vivian K. Mushahwar
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Stimulation ◽  
Motor Evoked Potential ◽  
H Reflex ◽  
Spinal Reflex ◽  
Lumbar Spinal Cord ◽  
Reflex Amplitude ◽  
Leg Cycling ◽  
Lumbar Spinal ◽  
Neurologically Intact

Coupling between cervical and lumbar spinal networks (cervico-lumbar coupling) is vital during human locomotion. Impaired cervico-lumbar coupling after neural injuries or diseases can be reengaged via simultaneous arm and leg cycling training. Sensorimotor circuitry including cervico-lumbar coupling may further be enhanced by non-invasive modulation of spinal circuity using transcutaneous spinal cord stimulation (tSCS). This project aimed to determine the effect of cervical, lumbar, or combined tSCS on spinal reflex (Hoffmann [H-]) and corticospinal (motor evoked potential [MEP]) excitability during a static or cycling cervico-lumbar coupling task. Fourteen neurologically intact study participants were seated in a recumbent leg cycling system. H-reflex and MEP amplitudes were assessed in the left flexor carpi radialis (FCR) muscle during two tasks (Static and Cycling) and four conditions: (1) No tSCS, (2) tSCS applied to the cervical enlargement (Cervical); (3) tSCS applied to the lumbar enlargement (Lumbar); (4) simultaneous cervical and lumbar tSCS (Combined). While cervical tSCS did not alter FCR H-reflex amplitude relative to No tSCS, lumbar tSCS significantly facilitated H-reflex amplitude by 11.1%, and combined cervical and lumbar tSCS significantly enhanced the facilitation to 19.6%. Neither cervical nor lumbar tSCS altered MEP amplitude alone (+4.9 and 1.8% relative to legs static, No tSCS); however, combined tSCS significantly increased MEP amplitude by 19.7% compared to No tSCS. Leg cycling alone significantly suppressed the FCR H-reflex relative to static, No tSCS by 13.6%, while facilitating MEP amplitude by 18.6%. When combined with leg cycling, tSCS was unable to alter excitability for any condition. This indicates that in neurologically intact individuals where interlimb coordination and corticospinal tract are intact, the effect of leg cycling on cervico-lumbar coupling and corticospinal drive was not impacted significantly with the tSCS intensity used. This study demonstrates, for the first time, that tonic activation of spinal cord networks through multiple sites of tSCS provides a facilitation of both spinal reflex and corticospinal pathways. It remains vital to determine if combined tSCS can influence interlimb coupling after neural injury or disease when cervico-lumbar connectivity is impaired.

Neural Coupling Between the Arms and Legs During Rhythmic Locomotor-Like Cycling Movement

2007 ◽  
Vol 97 (2) ◽  
pp. 1809-1818 ◽  
Author(s):  
Jaclyn E. Balter ◽  
E. Paul Zehr
Keyword(s):  
Arm Movement ◽  
Human Locomotion ◽  
Superficial Peroneal Nerve ◽  
Cutaneous Reflexes ◽  
Leg Muscles ◽  
Arm Cycling ◽  
Relative Contribution ◽  
Leg Cycling ◽  
Leg Movement ◽  
Stimulation Of

Neuronal coupling between the arms and legs allowing coordinated rhythmic movement during locomotion is poorly understood. We used the modulation of cutaneous reflexes to probe this neuronal coupling between the arms and legs using a cycling paradigm. Participants performed rhythmic cycling with arms, legs, or arms and legs together. We hypothesized that any contributions from the arms would be functionally linked to locomotion and would thus be phase-dependent. Reflexes were evoked by electrical stimulation of the superficial peroneal nerve at the ankle, and electromyography (EMG) was recorded from muscles in the arms and legs. The main finding was that the relative contribution from the arms and legs was linked to the functional state of the legs. For example, in tibialis anterior, the largest contribution from arm movement [57% variance accounted for (VAF), P < 0.05] was during the leg power phase, whereas the largest from leg movement (71% VAF, P < 0.05) was during leg cycling recovery. Thus the contribution from the arms was functionally gated throughout the locomotor cycle in a manner that appears to support the action of the legs. Additionally, the effect of arm cycling on reflexes in leg muscles when the legs were not moving was relatively minor; full expression of the effect of rhythmic arm movement was only observed when both the arms and legs were moving. Our findings provide experimental support for the interaction of rhythmic arm and leg movement during human locomotion.

Neural Control of Rhythmic Human Arm Movement: Phase Dependence and Task Modulation of Hoffmann Reflexes in Forearm Muscles

2003 ◽  
Vol 89 (1) ◽  
pp. 12-21 ◽  
Author(s):  
E. Paul Zehr ◽  
David F. Collins ◽  
Alain Frigon ◽  
Nienke Hoogenboom
Keyword(s):  
Neural Control ◽  
Arm Movement ◽  
H Reflex ◽  
Neural Mechanisms ◽  
Emg Activity ◽  
Reflex Amplitude ◽  
Forearm Muscles ◽  
Custom Made ◽  
Static Contraction ◽  
Leg Movement

Although we move our arms rhythmically during walking, running, and swimming, we know little about the neural control of such movements. Our working hypothesis is that neural mechanisms controlling rhythmic movements are similar in the human lumbar and cervical spinal cord. Thus reflex modulation during rhythmic arm movement should be similar to that seen during leg movement. Our main experimental hypotheses were that the amplitude of H-reflexes in the forearm muscles would be modulated during arm movement (i.e., phase-dependent) and would be inhibited during cycling compared with static contraction (i.e., task-dependent). Furthermore, to determine the locus of any modulation, we tested the effect that active and passive movement of the ipsilateral (relative to stimulated arm) and contralateral arm had on H-reflex amplitude. Subjects performed rhythmic arm cycling on a custom-made hydraulic ergometer in which the two arms could be constrained to move together (180° out of phase) or could rotate independently. Position of the stimulated limb in the movement cycle is described with respect to the clock face. H-reflexes were evoked at 12, 3, 6, and 9 o'clock positions during static contraction as well as during rhythmic arm movements. Reflex amplitudes were compared between tasks at equal M wave amplitudes and similar levels of electromyographic (EMG) activity in the target muscle. Surface EMG recordings were obtained bilaterally from flexor carpi radialis as well as from other muscles controlling the wrist, elbow, and shoulder. Compared with reflexes evoked during static contractions, movement of the stimulated limb attenuated H-reflexes by 50.8% ( P < 0.005), 65.3% ( P < 0.001), and 52.6% ( P < 0.001) for bilateral, active ipsilateral, and passive ipsilateral movements, respectively. In contrast, movement of the contralateral limb did not significantly alter H-reflex amplitude. H-reflexes were also modulated by limb position ( P < 0.005). Thus task- and phase-dependent modulation were observed in the arm as previously demonstrated in the leg. The data support the hypothesis that neural mechanisms regulating reflex pathways in the moving limb are similar in the human upper and lower limbs. However, the inhibition of H-reflex amplitude induced by contralateral leg movement is absent in the arms. This may reflect the greater extent to which the arms can be used independently.

Changes in H reflex and neuromechanical properties of the trapezius muscle after 5 weeks of eccentric training: a randomized controlled trial

2014 ◽  
Vol 116 (12) ◽  
pp. 1623-1631 ◽  
Author(s):  
Steffen Vangsgaard ◽  
Janet L. Taylor ◽  
Ernst A. Hansen ◽  
Pascal Madeleine
Keyword(s):  
Electrical Stimulation ◽  
Strength Training ◽  
Reference Group ◽  
Controlled Trial ◽  
Trapezius Muscle ◽  
Training Group ◽  
H Reflex ◽  
Eccentric Training ◽  
Voluntary Activity ◽  
Stimulation Of

Trapezius muscle Hoffman (H) reflexes were obtained to investigate the neural adaptations induced by a 5-wk strength training regimen, based solely on eccentric contractions of the shoulder muscles. Twenty-nine healthy subjects were randomized into an eccentric training group ( n = 15) and a reference group ( n = 14). The eccentric training program consisted of nine training sessions of eccentric exercise performed over a 5-wk period. H-reflex recruitment curves, the maximal M wave (Mmax), maximal voluntary contraction (MVC) force, rate of force development (RFD), and electromyographic (EMG) voluntary activity were recorded before and after training. H reflexes were recorded from the middle part of the trapezius muscle by electrical stimulation of the C3/4 cervical nerves; Mmax was measured by electrical stimulation of the accessory nerve. Eccentric strength training resulted in significant increases in the maximal trapezius muscle H reflex (Hmax) (21.4% [5.5–37.3]; P = 0.01), MVC force (26.4% [15.0–37.7]; P < 0.01), and RFD (24.6% [3.2–46.0]; P = 0.025), while no significant changes were observed in the reference group. Mmax remained unchanged in both groups. A significant positive correlation was found between the change in MVC force and the change in EMG voluntary activity in the training group ( r = 0.57; P = 0.03). These results indicate that the net excitability of the trapezius muscle H-reflex pathway increased after 5 wk of eccentric training. This is the first study to investigate and document changes in the trapezius muscle H reflex following eccentric strength training.

Thoracic Leg Control of Abdominal Extension in the Crayfish, Procambarus Clarkii

1981 ◽  
Vol 90 (1) ◽  
pp. 85-100
Author(s):  
CHARLES H. PAGE
Keyword(s):  
Procambarus Clarkii ◽  
Mean Values ◽  
Extensor Muscles ◽  
Carpal Joint ◽  
The Mean ◽  
Leg Movement ◽  
Abdominal Appendages ◽  
Thoracic And Abdominal ◽  
Abdominal Movement ◽  
Stimulation Of

Postural extensions of the abdomen of the crayfish, Procambarus clarkii, could be evoked by mechanical stimulation of a single thoracic leg. Movement of a single leg joint was sufficient to initiate an extension response. Vigorous abdominal extensions were initiated either by depression of the whole leg (WLD) or by flexion of the mero-carpal joint (MCF). Weaker extension responses were obtained by depression of the thoracic-coxal and coxo-basal joints. Similar stimulation of the chelipeds did not elicit an abdominal extension response. Single-frame analysis of motion pictures of crayfish responding to WLD or MCF stimulation of a 2nd thoracic leg showed that the responses evoked by the two different stimulus situations were nearly identical. They differed principally in the responses of the leg located contralateral to the stimulated leg. Movements of most of the cephalic, thoracic and abdominal appendages accompanied the abdominal extension response. Only the eyes remained stationary throughout the response. The mean values of the latencies for the initiation of appendage movement ranged from 125 to 204 ma; abdominal movement had a mean latency of about 220 ms. The abdominal extension reflex resulted from the activity of the tonic superficial extensor muscles. The deep phasic extensor muscles were silent during the response. The mean latencies for the initiation of superficial extensor muscle activity by WLD and MCF stimulation were 53·7 and 50·0 ms respectively.

Regulation of breathing at beginning of exercise

1963 ◽  
Vol 18 (6) ◽  
pp. 1183-1187 ◽  
Author(s):  
F. N. Craig ◽  
E. G. Cummings ◽  
W. V. Blevins
Keyword(s):  
Action Potential ◽  
Cycle Ergometer ◽  
Respiratory Drive ◽  
Muscle Action ◽  
Work Situation ◽  
Muscle Action Potential ◽  
Regulation Of Breathing ◽  
The Subject ◽  
Leg Movement

In initial 20-sec periods of running on the treadmill, raising the slope to 12% increased by 50% the integrated muscle action potential, recorded from the under side of the thigh, without affecting the ventilation in four men. Five men worked for 1 min at four tasks, two on the treadmill and two on the horizontal cycle ergometer. Each pair of tasks consisted of slow and rapid leg movement at the same rate of work. Ventilation often continued at about the resting rate for the first few seconds of work, unaffected in any significant way by frequency of leg movement. In the subject responding to the onset of exercise by a sudden sharp involuntary increase in ventilation, the nature of the nervous respiratory drive is not clear. Whatever drive arises from the work itself may be strongly modified by training or by complexities in the work situation. leg movement; muscle action potential; nervous respiratory drive Submitted on May 16, 1963

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