Sensitivity of monosynaptic test reflexes to facilitation and inhibition as a function of the test reflex size: a study in man and the cat

Crone, C; Hultborn, Hans; Mazieres, L.; Morin, Catherine; Nielsen, Jens Bo; Pierrot-Deseilligny, E

doi:10.1007/bf00230098

Cited by 481 publications

(337 citation statements)

References 24 publications

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“…4B) and compared to those obtained when the two conditioning stimuli were applied. Since it has been shown (Crone, Hultborn, Mazieres, Morin, Nielsen, Pierrot-Deseilligny, 1990) Fig. 4C.…”

Section: Reciprocal Inhibition In the Human Upper Limb 281mentioning

confidence: 92%

Reciprocal Ia inhibition between elbow flexors and extensors in the human.

Katz

Pénicaud

Rossi

1991

The Journal of Physiology

113

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SUMMARY1. Reciprocal inhibition between elbow flexor and extensor muscles (biceps and triceps brachii) has been investigated in nine healthy subjects. Two techniques were used to assess changes in motoneurone excitability after stimulation of antagonist muscle afferents: (1) monosynaptic reflexes elicited by a mechanical stimulation of the distal muscle tendon (tendon tap); (2) post-stimulus time histograms (PSTH) of voluntarily activated motor units.2. Electrical stimulation of the antagonist muscle nerve produced a short-latency and short-lasting inhibition of the flexor and extensor motoneurones. The amount of this inhibition was found to be similar in both motor nuclei.3. The inhibition could be evoked with conditioning electrical stimuli as low as 0 7 x motor threshold (MT) or by very weak tendon taps applied to the antagonist tendon. In the former case the threshold of this inhibition was found to be consistently increased after raising the threshold of Ia afferent fibres by a longlasting muscle vibration. Since a contribution from cutaneous afferent fibres was ruled out, it is concluded that this inhibition was Ia in origin.4. Post-stimulus time histograms of voluntarily activated triceps and biceps motor units were made following electrical stimulation of homonymous and antagonist muscle afferents. This enabled an estimate of the central synaptic delay of the inhibitory process. An average central delay of 0-94 ms in excess of that of monosynaptic facilitation was found, thus suggesting that the inhibitory process could be mediated by only one interneurone. 5. A conditioning reflex discharge elicited in the antagonist muscle by a tendon tap depressed or suppressed this inhibition. This depression was maximal when the reflex discharge was elicited 10-20 ms before the conditioning stimulus for the inhibition and never lasted more than 30 ms. It is argued that the only mechanism compatible with such a depression is the inhibitory activity of Renshaw cells acting on the pathway mediating reciprocal inhibition.6. We conclude that group Ia afferent fibres from elbow extensor and flexor

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“…4B) and compared to those obtained when the two conditioning stimuli were applied. Since it has been shown (Crone, Hultborn, Mazieres, Morin, Nielsen, Pierrot-Deseilligny, 1990) Fig. 4C.…”

Section: Reciprocal Inhibition In the Human Upper Limb 281mentioning

confidence: 92%

Reciprocal Ia inhibition between elbow flexors and extensors in the human.

Katz

Pénicaud

Rossi

1991

The Journal of Physiology

113

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“…A similar standardization of the accompanying EMG activity from the stretch reflex has already become standard. 51,52 Future aims may be to develop the methods further and to consider whether it will be feasible to develop new portable or semiportable devices that are easy to use in the clinical setting as described recently by Burridge et al…”

Section: Overall Evaluation Of Isokinetic Dynamometer Measurementsmentioning

confidence: 99%

Spasticity-assessment: a review

2006

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Study design: Review of the literature on the validity and reliability of assessment of spasticity and spasms. Objectives: Evaluate the most frequently used methods for assessment of spasticity and spasms, with particular focus on individuals with spinal cord lesions. Setting: Clinic for Spinal Cord Injuries, Rigshospitalet, University Hospital of Copenhagen, and Department of Medical Physiology, University of Copenhagen, Denmark. Methods: The assessment methods are grouped into clinical, biomechanical and electrophysiological, and the correlation between these is evaluated. Results: Clinical methods: For assessment of spasticity, the Ashworth and the modified Ashworth scales are commonly used. They provide a semiquantitative measure of the resistance to passive movement, but have limited interrater reliability. Guidelines for the testing procedures should be adhered to. Spasm frequency scales seem not to have been tested for reliability. Biomechanical methods such as isokinetic dynamometers are of value when an objective quantitative measure of the resistance to passive movement is necessary. They play a minor role in the daily clinical evaluation of spasticity. Electrophysiological methods: These techniques have provided valuable insight to the pathophysiological mechanisms involved in spasticity, but none of these techniques provide an easy and reliable assessment of spasticity for use in the daily clinic. Conclusion: A combination of electrophysiological and biomechanical techniques shows some promise for a full characterization of the spastic syndrome. There is a need of simple instruments, which provide a reliable quantitative measure with a low interrater variability.

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“…This approach also avoided contamination of the H-reflex by F waves evoked by antidromic activation of homonymous motor axons (Fisher, 1992). The sensitivity of monosynaptic reflexes to a variety of facilitatory and inhibitory effects is greatest for reflexes of moderate amplitude (Crone et al, 1990). To maximize our ability to detect these modulatory effects, the stimulus intensity was adjusted to produce a short latency (∼30 ms) response in the first dorsal interosseus with an amplitude equal to half of its maximal value for each subject.…”

Section: Delivery Of Mechanical and Electrical Stimulimentioning

confidence: 99%

Reflex responsiveness of a human hand muscle when controlling isometric force and joint position

Maluf

Barry

Riley

et al. 2007

Clinical Neurophysiology

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Objective-This study compared reflex responsiveness of the first dorsal interosseus muscle during two tasks that employ different strategies to stabilize the finger while exerting the same net muscle torque.Methods-Healthy human subjects performed two motor tasks that involved either pushing up against a rigid restraint to exert a constant isometric force equal to 20% of maximum, or maintaining a constant angle at the metacarpophalangeal joint while supporting an equivalent inertial load. Each task consisted of six 40-s contractions during which electrical and mechanical stimuli were delivered.Results-The amplitude of short and long latency reflex responses to mechanical stretch did not differ significantly between tasks. In contrast, reflexes evoked by electrical stimulation were significantly greater when supporting the inertial load.Conclusions-Agonist motor neurons exhibited heightened reflex responsiveness to synaptic input from heteronymous afferents when controlling the position of an inertial load. Task differences in the reflex response to electrical stimulation were not reflected in the response to mechanical perturbation, indicating a difference in the efficacy of the pathways that mediate these effects.Significance-Results from this study suggest that modulation of spinal reflex pathways may contribute to differences in the control of force and position during isometric contractions of the first dorsal interosseus muscle.

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Sensitivity of monosynaptic test reflexes to facilitation and inhibition as a function of the test reflex size: a study in man and the cat

Cited by 481 publications

References 24 publications

Reciprocal Ia inhibition between elbow flexors and extensors in the human.

Reciprocal Ia inhibition between elbow flexors and extensors in the human.

Spasticity-assessment: a review

Reflex responsiveness of a human hand muscle when controlling isometric force and joint position

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