Reassessment of H-reflex recovery curve using the double stimulation procedure

Kagamihara, Yasuhiro; Hayashi, Atsushi; Okuma, Yasuyuki; Nagaoka, Masanori; Nakajima, Yasoichi; Tanaka, Reisaku

doi:10.1002/(sici)1097-4598(199803)21:3<352::aid-mus9>3.0.co;2-9

Cited by 29 publications

(24 citation statements)

References 9 publications

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“…Such excitation could be caused by reafferent feedback activation induced by the substantial stimulation-evoked muscle twitch contractions and the subsequent relaxation. Reafferent feedback activation has been suggested to contribute to the facilitation of H reflexes elicited by double stimuli at interstimulus intervals of 100 -400 ms (Kagamihara et al 1998;Paillard 1959;Schiepatti 1987). Here postactivation depression and presynaptic inhibition presumably led to a longer-lasting reduction in reflex transmission when SCS was applied at 5-26 Hz, since even the larger responses within the periodic modulation patterns were smaller than the unconditioned initial response to the first stimulus of the respective train.…”

Section: Discussionmentioning

confidence: 99%

Periodic modulation of repetitively elicited monosynaptic reflexes of the human lumbosacral spinal cord

Hofstoetter

Danner

Freundl

et al. 2015

Journal of Neurophysiology

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Hofstoetter US, Danner SM, Freundl B, Binder H, Mayr W, Rattay F, Minassian K. Periodic modulation of repetitively elicited monosynaptic reflexes of the human lumbosacral spinal cord. J Neurophysiol 114: 400 -410, 2015. First published April 22, 2015 doi:10.1152/jn.00136.2015.-In individuals with motor-complete spinal cord injury, epidural stimulation of the lumbosacral spinal cord at 2 Hz evokes unmodulated reflexes in the lower limbs, while stimulation at 22-60 Hz can generate rhythmic burstlike activity. Here we elaborated on an output pattern emerging at transitional stimulation frequencies with consecutively elicited reflexes alternating between large and small. We analyzed responses concomitantly elicited in thigh and leg muscle groups bilaterally by epidural stimulation in eight motor-complete spinal cord-injured individuals. Periodic amplitude modulation of at least 20 successive responses occurred in 31.4% of all available data sets with stimulation frequency set at 5-26 Hz, with highest prevalence at 16 Hz. It could be evoked in a single muscle group only but was more strongly expressed and consistent when occurring in pairs of antagonists or in the same muscle group bilaterally. Latencies and waveforms of the modulated reflexes corresponded to those of the unmodulated, monosynaptic responses to 2-Hz stimulation. We suggest that the cyclical changes of reflex excitability resulted from the interaction of facilitatory and inhibitory mechanisms emerging after specific delays and with distinct durations, including postactivation depression, recurrent inhibition and facilitation, as well as reafferent feedback activation. The emergence of large responses within the patterns at a rate of 5.5/s or 8/s may further suggest the entrainment of spinal mechanisms as involved in clonus. The study demonstrates that the human lumbosacral spinal cord can organize a simple form of rhythmicity through the repetitive activation of spinal reflex circuits.

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Section: Discussionmentioning

confidence: 99%

Periodic modulation of repetitively elicited monosynaptic reflexes of the human lumbosacral spinal cord

Hofstoetter

Danner

Freundl

et al. 2015

Journal of Neurophysiology

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“…2B). When double stimulation procedure is used, it is well known that the second H-reflex is almost depressed if the interval is within several tens of milliseconds (Kagamihara et al 1998;Magladery et al 1952). In accordance with this well-known behavior, several subsequent responses were considerably depressed (Fig.…”

Section: Discussionmentioning

confidence: 99%

Sustained Muscle Contractions Maintained by Autonomous Neuronal Activity Within the Human Spinal Cord

Nozaki

Kawashima

Aramaki

et al. 2003

Journal of Neurophysiology

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. Sustained muscle contractions maintained by autonomous neuronal activity within the human spinal cord. J Neurophysiol 90: 2090 -2097, 2003. First published May 28, 2003 10.1152/jn.00200.2003. It is well known that muscle contraction can be easily evoked in the human soleus muscle by applying single-pulse electrical stimulation to the tibial nerve at the popliteal fossa. We herein reveal the unexpected phenomenon of muscle contractions that can be observed when train stimulation is used instead. We found, in 11 human subjects, that transient electrical train stimulation (1-ms pulses, 50 Hz, 2 s) was able to induce sustained muscle contractions in the soleus muscle that outlasted the stimulation period for greater than 1 min. Subjects were unaware of their own muscle activity, suggesting that this is an involuntary muscle contraction. In fact, the excitability of the primary motor cortex (M1) with the sustained muscle contractions evaluated by transcranial magnetic stimulation was lower than the excitability with voluntary muscle contractions even when both muscle contraction levels were matched. This finding indicates that M1 was less involved in maintaining the muscle contractions. Furthermore, the muscle contractions did not come from spontaneous activity of muscle fibers or from reverberating activity within closed neuronal circuits involving motoneurons. These conclusions were made based on the respective evidence: 1) the electromyographic activity was inhibited by stimulation of the common peroneal nerve that has inhibitory connections to the soleus motoneuron pool and 2) it was not abolished after stopping the reverberation (if any) for approximately 100 ms by inducing the silent period that followed an H-reflex. These findings indicate that the sustained muscle contractions induced in this study are most likely to be maintained by autonomous activity of motoneurons and/or interneurons within the human spinal cord.

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“…Paired spinally evoked motor potentials 50-ms apart (CTI-50) were identified and categorized as the conditioning (R1) and test (R2) responses in order to investigate the neural mechanism of post-stimulation modulation [16, 22, 24]. To quantify post-stimulation modulation of the responses, the inhibition ratio was calculated by dividing the magnitude of R2 by R1.…”

Section: Methodsmentioning

confidence: 99%

Effects of paired transcutaneous electrical stimulation delivered at single and dual sites over lumbosacral spinal cord

Sayenko

Atkinson

Floyd

et al. 2015

Neuroscience Letters

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It was demonstrated previously that transcutaneous electrical stimulation of multiple sites over the spinal cord is more effective in inducing robust locomotor behavior as compared to the stimulation of single sites alone in both animal and human models. To explore the effects and mechanisms of interactions during multi-site spinal cord stimulation we delivered transcutaneous electrical stimulation to the single or dual locations over the spinal cord corresponding to approximately L2 and S1 segments. Spinally evoked motor potentials in the leg muscles were investigated using single and paired pulses of 1 ms duration with conditioning-test intervals (CTIs) of 5 and 50 ms. We observed considerable post-stimulation modulatory effects which depended on CTIs, as well as on whether the paired stimuli were delivered at a single or dual locations, the rostro-caudal relation between the conditioning and test stimuli, and on the muscle studied. At CTI-5, the paired stimulation delivered at single locations (L2 or S1) provided strong inhibitory effects, evidenced by the attenuation of the compound responses as compared with responses from either single site. In contrast, during L2-S1 paradigm, the compound responses were potentiated. At CTI-50, the magnitude of inhibition did not differ among paired stimulation paradigms. Our results suggest that electrical stimuli delivered to dual sites over the lumbosacral enlargement in rostral-to-caudal order, may recruit different populations of motor neurons initially through projecting sensory and intraspinal connections and then directly, resulting in potentiation of the compound spinally evoked motor potentials. The interactive and synergistic effects indicate multi-segmental convergence of descending and ascending influences on the neuronal circuitries during electrical spinal cord stimulation.

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Reassessment of H-reflex recovery curve using the double stimulation procedure

Cited by 29 publications

References 9 publications

Periodic modulation of repetitively elicited monosynaptic reflexes of the human lumbosacral spinal cord

Periodic modulation of repetitively elicited monosynaptic reflexes of the human lumbosacral spinal cord

Sustained Muscle Contractions Maintained by Autonomous Neuronal Activity Within the Human Spinal Cord

Effects of paired transcutaneous electrical stimulation delivered at single and dual sites over lumbosacral spinal cord

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