Modulation of the soleus H-reflex during pedalling in normal humans and in patients with spinal spasticity.

Boorman, G. I.; Becker, Werner J.; Morrice, B. L.; Lee, R G

doi:10.1136/jnnp.55.12.1150

Cited by 45 publications

(22 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Several previous studies have reported a similar modulation of the SOL H reflex with the background EMG activity during bicycling as we have reported here (Brooke et al 1992;Boorman et al 1992). A basically similar modulation has also been observed in relation to treadmill walking and running (Capaday and Stein 1986;Crenna and Frigo 1987;Simonsen and DyhrePoulsen 1999).…”

Section: Modulation Of H Reflexes and Mepssupporting

confidence: 70%

“…Comparison of H reflexes and MEPs is commonly used either to provide evidence of changes in cortical excitability in relation to fatigue (Brasil-Neto et al 1993a) and plasticity (Brasil-Neto et al 1993b;Schiepatti et al 1996) or alternatively to provide evidence of changes in presynaptic inhibition of Ia afferents (Berardelli et al 1987). The reasoning behind this is that the H reflex and MEP are both assumed to be mainly monosynaptic in origin and to activate the same population of motoneurons.…”

Section: Comparison Of H Reflexes and Mepsmentioning

confidence: 99%

“…Although the biomechanics of bicycling has been investigated thoroughly (Ericson 1986;Hull and Jorge 1985), only few studies have addressed the central control mechanisms (Boorman et al 1992;Brooke et al 1992;Zehr et al 2001). There are some obvious methodological advantages of studying bicycling.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Modulation of Transmission in the Corticospinal and Group Ia Afferent Pathways to Soleus Motoneurons During Bicycling

Pyndt

Nielsen

2003

Journal of Neurophysiology

View full text Add to dashboard Cite

Pyndt, H. S. and J. B. Nielsen. Modulation of transmission in the corticospinal and group Ia afferent pathways to soleus motoneurons during bicycling. J Neurophysiol 89: 304 -314, 2003. 10.1152/jn.00386.2002. Transmission in the corticospinal and Ia pathways to soleus motoneurons was investigated in healthy human subjects during bicycling. Soleus H reflexes and motor evoked potentials (MEPs) after transcranial magnetic stimulation (TMS) were modulated similarly during the crank cycle being large during downstroke [concomitant with soleus background electromyographic (EMG) activity] and small during upstroke. Tibialis anterior MEPs were in contrast large during upstroke and small during downstroke. The soleus H reflexes and MEPs were also recorded during tonic plantarflexion at a similar ankle joint position, corresponding ankle angle, and matched background EMG activity as during the different phases of bicycling. Relative to their size during tonic plantarflexion, the MEPs were found to be facilitated in the early part of downstroke during bicycling, whereas the H reflexes were depressed in the late part of downstroke. The intensity of TMS was decreased below MEP threshold and used to condition the soleus H reflex. At short intervals (conditioning-test intervals of Ϫ3 to Ϫ1 ms), TMS produced a facilitation of the H reflex that is in all likelihood caused by activation of the fast monosynaptic corticospinal pathway. This facilitation was significantly larger in the early part of downstroke during bicycling than during tonic plantarflexion. This suggests that the increased MEP during downstroke was caused by changes in transmission in the fast monosynaptic corticospinal pathway. To investigate whether the depression of H reflexes in the late part of downstroke was caused by increased presynaptic inhibition of Ia afferents, the soleus H reflex was conditioned by stimulation of the femoral nerve. At a short interval (conditioning-test interval: Ϫ7 to Ϫ5 ms), the femoral nerve stimulation produced a facilitation of the H reflex that is mediated by the heteronymous monosynaptic Ia pathway from the femoral nerve to soleus motoneurons. Within the initial 0.5 ms after its onset, the size of this facilitation depends on the level of presynaptic inhibition of the Ia afferents, which mediate the facilitation. The size of the facilitation was strongly depressed in the late part of downstroke, compared with the early part of downstroke, suggesting that increased presynaptic inhibition was indeed responsible for the depression of the H reflex. These findings suggest that there is a selectively increased transmission in the fast monosynaptic corticospinal pathway to soleus motoneurons in early downstroke during bicycling. It would seem likely that one cause of this is increased excitability of the involved cortical neurons. The increased presynaptic inhibition of Ia afferents in late downstroke may be of importance for depression of stretch reflex activity before and during upstroke.

show abstract

Section: Modulation Of H Reflexes and Mepssupporting

confidence: 70%

Section: Comparison Of H Reflexes and Mepsmentioning

confidence: 99%

See 1 more Smart Citation

Modulation of Transmission in the Corticospinal and Group Ia Afferent Pathways to Soleus Motoneurons During Bicycling

Pyndt

Nielsen

2003

Journal of Neurophysiology

View full text Add to dashboard Cite

show abstract

“…Previous studies have reported that passive lower-leg motion, such as cycling, stepping, and ankle joint movement, can induce H-reflex modulation, which depends on the sensory input due to the passive joint motions (Boorman et al, 1992;Brooke et al, 1995;Misiaszek et al, 1995;Pinniger et al, 2001). The results of this study further revealed that the sensory information accompanied with a passive upright posture is capable of modulating both the H-reflex and stretch reflex excitability of the soleus muscle.…”

Section: Functional Implicationsupporting

confidence: 57%

Enhanced stretch reflex excitability in the soleus muscle during passive standing posture in humans

Shimba

Kawashima

Ohta

et al. 2010

Journal of Electromyography and Kinesiology

View full text Add to dashboard Cite

“…Previous reports have shown that the soleus muscle is activated during flexion of the foot (Houlé et al, 1999). In humans, the soleus muscle, which is also activated during flexion when pedaling, has been shown to be much smaller during passive than during active cycling, which requires force generation (Boorman et al, 1992). In these conditions, it is unlikely that much loading occurs during our bicycle training paradigm.…”

Section: Restoration Of Frequency-dependent Depression Is Not Load-dementioning

confidence: 80%

Activity-Dependent Increase in Neurotrophic Factors Is Associated with an Enhanced Modulation of Spinal Reflexes after Spinal Cord Injury

Côté

Azzam²,

Lemay³

et al. 2011

Journal of Neurotrauma

169

158

View full text Add to dashboard Cite

Activity-based therapies such as passive bicycling and step-training on a treadmill contribute to motor recovery after spinal cord injury (SCI), leading to a greater number of steps performed, improved gait kinematics, recovery of phase-dependent modulation of spinal reflexes, and prevention of decrease in muscle mass. Both tasks consist of alternating movements that rhythmically stretch and shorten hindlimb muscles. However, the paralyzed hindlimbs are passively moved by a motorized apparatus during bike-training, whereas locomotor movements during step-training are generated by spinal networks triggered by afferent feedback. Our objective was to compare the task-dependent effect of bike-and step-training after SCI on physiological measures of spinal cord plasticity in relation to changes in levels of neurotrophic factors. Thirty adult female Sprague-Dawley rats underwent complete spinal transection at a low thoracic level (T12). The rats were assigned to one of three groups: bike-training, step-training, or no training. The exercise regimen consisted of 15 min/d, 5 days/week, for 4 weeks, beginning 5 days after SCI. During a terminal experiment, H-reflexes were recorded from interosseus foot muscles following stimulation of the tibial nerve at 0.3, 5, or 10 Hz. The animals were sacrificed and the spinal cords were harvested for Western blot analysis of the expression of neurotrophic factors in the lumbar spinal cord. We provide evidence that bike-and step-training significantly increase the levels of brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and NT-4 in the lumbar enlargement of SCI rats, whereas only step-training increased glial cell-derived neurotrophic factor (GDNF) levels. An increase in neurotrophic factor protein levels that positively correlated with the recovery of H-reflex frequency-dependent depression suggests a role for neurotrophic factors in reflex normalization.

show abstract

Modulation of the soleus H-reflex during pedalling in normal humans and in patients with spinal spasticity.

Cited by 45 publications

References 22 publications

Modulation of Transmission in the Corticospinal and Group Ia Afferent Pathways to Soleus Motoneurons During Bicycling

Modulation of Transmission in the Corticospinal and Group Ia Afferent Pathways to Soleus Motoneurons During Bicycling

Enhanced stretch reflex excitability in the soleus muscle during passive standing posture in humans

Activity-Dependent Increase in Neurotrophic Factors Is Associated with an Enhanced Modulation of Spinal Reflexes after Spinal Cord Injury

Contact Info

Product

Resources

About