The excitability of a motoneuron pool assessed by the H-reflex method is correlated with the susceptibility of Ia terminals to repetitive discharges in humans

Komiyama, Tomoyoshi; Kawai, Kazutake; Fumoto, Masaki

doi:10.1016/s0006-8993(99)01301-3

Cited by 11 publications

(5 citation statements)

References 16 publications

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“…Our results demonstrate the greatest magnitude of modulation of spinally evoked motor potentials occurred when the test response was at or near RRmax (Figure 5). The maximal slope of the recruitment curve in different muscles has been suggested to indicate the rate of afferent recruitment (Funase et al, 1994; Komiyama et al, 1999; Sekiguchi et al, 2003), may depend on the tonic level of presynaptic inhibition (Pierrot-Deseilligny and Burke, 2005; Sayenko et al, 2015a), and may be attributed to the type, number, and size of the motor neurons (Pierrot-Deseilligny and Burke, 2005). Thus, the utilized normalization approach is supported by the physiological meaning of RRmax, and can serve as a real-time or post hoc technique during neurophysiological or functional assessment, when a quantitative characterization of the conditioning effects among different motor pools is advantageous.…”

Section: Discussionmentioning

confidence: 99%

Vestibulospinal and Corticospinal Modulation of Lumbosacral Network Excitability in Human Subjects

et al. 2018

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As part of a project aimed to develop a novel, non-invasive techniques for comprehensive assessment of supraspinal-spinal connectivity in humans, the present study sought to explore the convergence of descending vestibulospinal and corticospinal pathways onto lumbosacral motor pools. Transcutaneous electrical spinal stimulation-evoked motor potentials were recorded from knee and ankle flexors and extensors in resting neurologically intact participants. Descending influences on lumbosacral motor neurons were studied using galvanic vestibular (GVS) or transcranial magnetic stimulation (TMS) to elicit descending vestibulospinal or corticospinal volleys, respectively. Facilitatory conditioning effects of descending corticospinal volleys were manifested by a significant increase of spinally evoked motor potentials in recorded knee and ankle muscles bilaterally, and were observed at the 10–30 ms conditioning-test intervals (CTIs); whereas, facilitatory conditioning effects of vestibulospinal volleys manifested at longer latencies (CTIs of 90 and 110 ms), and lasted up to 250 ms. TMS mediated volleys revealed the conditioning effects at both short and long latencies, suggestive of both direct and indirect influence. In contrast, vestibulospinally mediated conditioning effects occurred at longer latencies, consistent with this pathway’s known anatomical and functional interfaces with other descending systems including the reticulospinal pathway and, suggestively, propriospinal interneurons. Our work demonstrates the utility and sensitivity of transcutaneous spinal stimulation in human neurophysiological studies as a technique for quantitative characterization of excitatory conditioning effects in multiple lumbosacral motor pools, obtained through descending pathways. This characterization becomes critical in understanding the neuroplasticity in the central nervous system during motor learning and neurological recovery.

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Section: Discussionmentioning

confidence: 99%

Vestibulospinal and Corticospinal Modulation of Lumbosacral Network Excitability in Human Subjects

et al. 2018

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“…Abbruzzese et al 2) reported that the amplitude of the H-reflex in the brachioradialis muscle was smaller during lengthening than shortening contractions. Sekiguchi et al 10) compared the maximal H-reflex and the ratio of the slope in the ascending part of the H and M recruitment curves (Hslp/ Mslp) 65,66) between lengthening and shortening contractions in the soleus muscle. The Hslp/Mslp indicates the reflex gain of the monosynaptic spinal reflex pathway, as well as the recruitment gain of the motoneurons.…”

Section: Neural Control Strategy Underlying Lengthening Contractionsmentioning

confidence: 99%

Neural control of muscle lengthening: Task- and muscle-specificity

Sekiguchi

Nakazawa

Hortobágyi

2013

JPFSM

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We accomplish activities of daily living through a combination of or isolated isometric, shortening (concentric), lengthening (eccentric) contractions regarded as fundamental patterns of muscle activation. It has been widely recognized that a unique neural strategy may control lengthening contractions but it is still unclear if this neural strategy is uniform across muscles. Here we review evidence for task-specific differences in neural control of muscle lengthening and shortening as indexed by surface electromyographic activity, corticospinal excitability, anatomical properties, and motor unit behavior. The emerging hypothesis is that the neural control of task-specificity associated with muscle lengthening and shortening may not be uniform across all healthy human muscles.

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“…Thus, it can be inferred that as stimulus intensity is increased, additional α-motoneurons are being The slope of the line (B) described the increase in H-reflex amplitude per unit increase in stimulus intensity and was called H-slope (H slp ). A change in the ascending slope of the H-reflex recruitment curve will represent a change in the excitability of the α-motoneuron pool (Funase et al, 1994;Komiyama, Kawai, & Fumoto, 1999). A steeper slope reflects greater motoneuron excitability and a flatter slope reflects a lesser degree of motoneuron excitability.…”

Section: Linear Regression Analysis Of H-reflex and M-wave Recruitment mentioning

confidence: 99%

“…In the third method the data between H th and H max which produced the highest correlation coefficient (R 2 ) were used for plotting the linear regression line (Funase et al, 1996). The fourth method was introduced by Komiyama et al (1999).…”

Section: Calculation Of H-slope (H Slp )mentioning

confidence: 99%