Effect of afferent feedback and central motor commands on soleus H-reflex suppression during arm cycling

2012 ◽  
Vol 108 (11) ◽  
pp. 3049-3058 ◽  
Author(s):  
S. R. Hundza ◽  
Geoff C. de Ruiter ◽  
M. Klimstra ◽  
E. Paul Zehr
Keyword(s):  
Primary Source ◽  
Arm Movement ◽  
H Reflex ◽  
Afferent Feedback ◽  
Reflex Modulation ◽  
Muscle Vibration ◽  
Reflex Amplitude ◽  
Motor Commands ◽  
Arm Cycling ◽  
Central Motor Commands

Suppression of soleus H-reflex amplitude in stationary legs is seen during rhythmic arm cycling. We examined the influence of various arm-cycling parameters on this interlimb reflex modulation to determine the origin of the effect. We previously showed the suppression to be graded with the frequency of arm cycling but not largely influenced by changes in peripheral input associated with crank length. Here, we more explicitly explored the contribution of afferent feedback related to arm movement on the soleus H-reflex suppression. We explored the influence of load and rate of muscle stretch by manipulating crank-load and arm-muscle vibration during arm cycling. Furthermore, internally driven (“Active”) and externally driven (“Passive”) arm cycling was compared. Soleus H-reflexes were evoked with tibial nerve stimulation during stationary control and rhythmic arm-cycling conditions, including: 1) six different loads; 2) with and without vibration to arm muscles; and 3) Active and Passive conditions. No significant differences were seen in the level of suppression between the different crank loads or between conditions with and without arm-muscle vibration. Furthermore, in contrast to the clear effect seen during active cycling, passive arm cycling did not significantly suppress the soleus H-reflex amplitude. Current results, in conjunction with previous findings, suggest that the afferent feedback examined in these studies is not the primary source responsible for soleus H-reflex suppression. Instead, it appears that central motor commands (supraspinal or spinal in origin) associated with frequency of arm cycling are relatively more dominant sources.

Effect of Rhythmic Arm Movement on Reflexes in the Legs: Modulation of Soleus H-Reflexes and Somatosensory Conditioning

2004 ◽  
Vol 91 (4) ◽  
pp. 1516-1523 ◽  
Author(s):  
Alain Frigon ◽  
David F. Collins ◽  
E. Paul Zehr
Keyword(s):  
Spinal Cord ◽  
Nerve Stimulation ◽  
Presynaptic Inhibition ◽  
Arm Movement ◽  
Common Peroneal Nerve ◽  
H Reflex ◽  
Reflex Amplitude ◽  
Lumbosacral Spinal Cord ◽  
Arm Cycling ◽  
Shoulder Flexion

During locomotor tasks such as walking, running, and swimming, the arms move rhythmically with the legs. It has been suggested that connections between the cervical and lumbosacral spinal cord may mediate some of this interlimb coordination. However, it is unclear how these interlimb pathways modulate reflex excitability during movement. We hypothesized that rhythmic arm movement would alter the gain of reflex pathways in the stationary leg. Soleus H-reflexes recorded during arm cycling were compared with those recorded at similar positions with the arms stationary. Nerve stimulation was delivered with the right arm at approximately 70° shoulder flexion or 10° shoulder extension. H-reflexes were evoked alone (unconditioned) or with sural or common peroneal nerve (CP) conditioning to decrease or increase soleus IA presynaptic inhibition, respectively. Both conditioning stimuli were also delivered with no H-reflex stimulation. H-reflex amplitudes were compared at similar M-wave amplitudes and activation levels of the soleus. Arm cycling significantly reduced ( P < 0.05) unconditioned soleus H-reflexes at shoulder flexion by 21.7% and at shoulder extension by 8.8% compared with static controls. The results demonstrate a task-dependent modulation of soleus H-reflexes between arm cycling and stationary trials. Sural nerve stimulation facilitated H-reflexes at shoulder extension but not at shoulder flexion during static and cycling trials. CP nerve stimulation significantly reduced H-reflex amplitude in all conditions. Reflexes in soleus when sural and CP nerve stimulation were delivered alone, were not different between cycling and static trials; thus the task-dependent change in H reflex amplitude was not due to changes in motoneuron excitability. Therefore modulation occurred at a pre-motoneuronal level, probably by presynaptic inhibition of the IA afferent volley. Results indicate that neural networks coupling the cervical and lumbosacral spinal cord in humans are activated during rhythmic arm movement. It is proposed that activation of these networks may assist in reflex linkages between the arms and legs during locomotor tasks.

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.

Phase-dependent modulation of soleus H-reflex amplitude induced by rhythmic arm cycling

2010 ◽  
Vol 475 (1) ◽  
pp. 7-11 ◽  
Author(s):  
Geoff C. de Ruiter ◽  
Sandra R. Hundza ◽  
E. Paul Zehr
Keyword(s):  
H Reflex ◽  
Reflex Amplitude ◽  
Arm Cycling

scholarly journals Rectus femoris hyperreflexia predicts knee flexion angle in Stiff-Knee gait after stroke

2019 ◽  
Author(s):  
Tunc Akbas ◽  
Kyoungsoon Kim ◽  
Kathleen Doyle ◽  
Kathleen Manella ◽  
Robert Lee ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Rectus Femoris ◽  
H Reflex ◽  
Flexion Angle ◽  
Reflex Modulation ◽  
Knee Flexion Angle ◽  
Healthy Individuals ◽  
Reflex Amplitude ◽  
Post Stroke ◽  
Stiff Knee

AbstractStiff-knee gait (SKG) after stroke is often accompanied by decreased knee flexion angle during the swing phase. The decreased knee flexion has been hypothesized to originate from excessive quadriceps activation. However, it is unclear whether this activation is due to poor timing or hyperreflexia, both common post-stroke impairments. The goal of this study was to investigate the relation between quadriceps hyperreflexia in post-stroke SKG with knee flexion angle during walking. The rectus femoris (RF) H-reflex was recorded in eleven participants with post-stroke SKG and ten healthy controls during standing and walking during toe-off. In order to separate the effects of poorly timed quadriceps muscle activation from hyperreflexia, healthy individuals voluntarily increased quadriceps activity using RF electromyographic (EMG) biofeedback during standing and pre-swing upon H-reflex stimulation. We observed a negative correlation (R = −0.92, p=0.001) between knee flexion angle and RF H-reflexes in post-stroke SKG. In contrast, H-reflex amplitude in healthy individuals in presence (R = 0.47, p = 0.23) or absence (R = −0.17, p = 0.46) of increased RF activity had no correlation with knee flexion angle. The RF H-reflex amplitude differed between standing and walking in healthy individuals, including when RF activity was increased voluntarily (d = 2.86, p = 0.007), but was not observed post-stroke (d =0.73, p = 0.296). Thus, RF reflex modulation is impaired in post-stroke SKG. Further, RF hyperreflexia, as opposed to overactivity, may play a role in knee flexion kinematics in post-stroke SKG. Interventions targeting self-regulated quadriceps hyperreflexia may be effective in promoting better neural control of the knee joint and thus better quality of walking post-stroke.

Possible contributions of CPG activity to the control of rhythmic human arm movement

2004 ◽  
Vol 82 (8-9) ◽  
pp. 556-568 ◽  
Author(s):  
E Paul Zehr ◽  
Timothy J Carroll ◽  
Romeo Chua ◽  
David F Collins ◽  
Alain Frigon ◽  
...  
Keyword(s):  
Motor Control ◽  
Neural Control ◽  
Arm Movement ◽  
Rhythmic Movement ◽  
Lower Limbs ◽  
Reflex Modulation ◽  
Arm Cycling ◽  
Reflex Reversal ◽  
Arm Muscles ◽  
Leg Movement

There is extensive modulation of cutaneous and H-reflexes during rhythmic leg movement in humans. Mechanisms controlling reflex modulation (e.g., phase- and task-dependent modulation, and reflex reversal) during leg movements have been ascribed to the activity of spinal central pattern generating (CPG) networks and peripheral feedback. Our working hypothesis has been that neural mechanisms (i.e., CPGs) controlling rhythmic movement are conserved between the human lumbar and cervical spinal cord. Thus reflex modulation during rhythmic arm movement should be similar to that for rhythmic leg movement. This hypothesis has been tested by studying the regulation of reflexes in arm muscles during rhythmic arm cycling and treadmill walking. This paper reviews recent studies that have revealed that reflexes in arm muscles show modulation within the movement cycle (e.g., phase-dependency and reflex reversal) and between static and rhythmic motor tasks (e.g., task-dependency). It is concluded that reflexes are modulated similarly during rhythmic movement of the upper and lower limbs, suggesting similar motor control mechanisms. One notable exception to this pattern is a failure of contralateral arm movement to modulate reflex amplitude, which contrasts directly with observations from the leg. Overall, the data support the hypothesis that CPG activity contributes to the neural control of rhythmic arm movement.Key words: central pattern generator, locomotion, motor control, neural control.

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.

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