Reciprocal group I inhibition on triceps surae motoneurons in man.

Mizuno, Yoshikuni; Tanaka, Reisaku; Yanagisawa, Nobuo

doi:10.1152/jn.1971.34.6.1010

Cited by 216 publications

(181 citation statements)

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“…The level of Ia presynaptic inhibition was assessed with two methods: D1 inhibition and heteronymous Ia facilitation. The D1-inhibition method (Mizuno et al 1971) tests the excitability of the PAD interneurons by stimulating the Ia afferents originating from the antagonist muscle (conditioning stimulation) before applying the test stimulus to the nerve supplying the agonist muscle (test stimulation; H reflex). The heteronymous Ia facilitation method provides a measure of the ongoing presynaptic inhibition imposed on heteronymous Ia afferents that synapse with the target motor neuron pool (Hultborn et al 1987a,b).…”

Section: Discussionmentioning

confidence: 99%

“…Electrical stimuli were used to elicit test H reflexes and to provide conditioning stimuli that produced either D1 inhibition (Mizuno et al 1971) or heteronymous Ia facilitation (Hultborn et al 1987a,b). The stimuli were elicited by electrical stimulation (Grass S88K, AstraMed, West Warwick, RI; 1-ms rectangular pulse) of the target nerve via a constant current unit (Model CCU1, Astra-Med) that was connected to adhesive surface electrodes (Conmed, Utica, NY) placed in a bipolar configuration.…”

Section: Electrical Stimulationmentioning

confidence: 99%

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Presynaptic Modulation of Ia Afferents in Young and Old Adults When Performing Force and Position Control

Baudry

Maerz

Enoka

2010

Journal of Neurophysiology

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Baudry S, Maerz AH, Enoka RM. Presynaptic modulation of Ia afferents in young and old adults when performing force and position control. J Neurophysiol 103: 623-631, 2010. First published November 25, 2009 doi:10.1152/jn.00839.2009. The present work investigated presynaptic modulation of Ia afferents in the extensor carpi radialis (ECR) when young and old adults exerted a wrist extension force either to support an inertial load (position control) or to achieve an equivalent constant torque against a rigid restraint (force control) at 5, 10, and 15% of the maximal force. H reflexes were evoked in the ECR by stimulating the radial nerve above the elbow. A conditioning stimulus was applied to the median nerve above the elbow to assess presynaptic inhibition of homonymous Ia afferents (D1 inhibition) or at the wrist (palmar branch) to assess the ongoing presynaptic inhibition of heteronymous Ia afferents that converge onto the ECR motor neuron pool (heteronymous Ia facilitation). The young adults had less D1 inhibition and greater heteronymous Ia facilitation during the position task (79 and 132.1%, respectively) compared with the force task (69.1 and 115.1%, respectively, P Ͻ 0.05). In contrast, the old adults exhibited no difference between the two tasks for either D1 inhibition (ϳ72%) or heteronymous Ia facilitation (ϳ114%). Contraction intensity did not influence the amount of D1 inhibition or heteronymous Ia facilitation for either group of subjects. The amount of antagonist coactivation was similar between tasks for young adults, whereas it was greater in the position task for old adults (P ϭ 0.02). These data indicate that in contrast to young adults, old adults did not modulate presynaptic inhibition of Ia afferents when controlling the position of a compliant load but rather increased coactivation of the antagonist muscle.

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Section: Discussionmentioning

confidence: 99%

Section: Electrical Stimulationmentioning

confidence: 99%

Presynaptic Modulation of Ia Afferents in Young and Old Adults When Performing Force and Position Control

Baudry

Maerz

Enoka

2010

Journal of Neurophysiology

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“…Increased presynaptic inhibition, measured by the long-latency depression (elicited by common peroneal nerve stimulation) and the femoral nerve facilitation of the SOL H-reflex, was observed recently to be involved in the depression of the SOL H-reflex after a visuomotor training task (Perez et al 2005). The long-latency depression of the H-reflex reflects the level of presynaptic inhibition of SOL Ia afferents evoked by peripheral nerve stimulation (Mizuno et al 1971), whereas the size of the femoral nerve facilitation reflects the size of the monosynaptic excitatory postsynaptic potential in the SOL motoneurons evoked by the activation of Ia afferents from the quadriceps muscle, and changes in its size are considered to indicate changes in the ongoing level of presynaptic inhibition of the Ia afferents (Hultborn et al 1987a,b). Furthermore, Nielsen and Kagamihara (1993) demonstrated that the depression of the H-reflex during cocontraction, compared with isolated plantar- flexion, was also caused by increased presynaptic inhibition of the Ia afferents.…”

Section: Mechanisms Contributing To the H-reflex And Mep Depressionmentioning

confidence: 98%

Task-Specific Depression of the Soleus H-Reflex After Cocontraction Training of Antagonistic Ankle Muscles

Perez

Lundbye‐Jensen

Nielsen

2007

Journal of Neurophysiology

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Perez MA, Lundbye-Jensen J, Nielsen JB. Task-specific depression of the soleus H-reflex after cocontraction training of antagonistic ankle muscles. J Neurophysiol 98: 3677-3687, 2007. First published October 17, 2007 doi:10.1152/jn.00988.2007. Ballet dancers have small soleus (SOL) H-reflex amplitudes, which may be related to frequent use of cocontraction of antagonistic ankle muscles. Indeed, SOL H-reflexes are depressed during cocontraction compared with plantarflexion at matched background EMG level. We investigated the effect of 30-min training of simultaneous activation of ankle dorsiand plantarflexor muscles (cocontraction task) on the SOL H-reflex in 10 healthy volunteers. Measurements were taken during cocontraction. After training, there was a significant improvement in the ability of the subjects to perform a stable cocontraction. SOL H-reflex recruitment curves and H-max/M-max ratios were decreased after cocontraction training but not after 30 min of static dorsi or plantarflexion. The decreased H-reflex size correlated with improved motor performance. No changes in SOL and tibialis anterior (TA) EMG activity or EMG power were observed, suggesting that increased presynaptic inhibition of Ia afferents is a likely mechanism for H-reflex depression. In different sessions we measured SOL and TA motor-evoked potentials (MEPs) by using transcranial magnetic stimulation (TMS), TMS-elicited suppression of SOL EMG, and coherence between electroencephalographic (EEG) activity (Cz) and TA and SOL EMG. SOL and TA MEPs were depressed, whereas TMSelicited suppression of SOL EMG and coherence were increased after training. Decreased excitability of corticospinal neurons due to increased intracortical inhibition seems a likely explanation of these observations. Our results indicate that the depression in H-reflex observed during a cocontraction task can be trained and that repeated performance of tasks involving cocontraction may lead to prolonged changes in reflex and corticospinal excitability.

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“…1). The decrease of H-reflex with such a conditioning technique is attributed to an increased excitability of primary afferent depolarization interneurons, thus reflecting an increased presynaptic inhibition of SOL Ia afference (Mizuno et al 1971). Here, the conditioning stimulus was applied to the branch of the common peroneal nerve with two AgCl surface electrodes (8 mm diameter) placed at the upper part of the anterolateral side of the leg, distal to the caput fibulae (Forget et al 1989).…”

Section: Pns (Sessions 3 and 4)mentioning

confidence: 99%