Effect of cutaneous nerve stimulation on voluntary and stretch reflex electromyographic activity in wrist flexors in humans.

Becker, Werner J.; Hayashi, Ryoichi; Lee, R G; White, David G.

doi:10.1113/jphysiol.1987.sp016381

Cited by 9 publications

(5 citation statements)

References 21 publications

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“…Becker etal. explained the discrepancy as the difference in the stimulus parameters employed, namely, 'lower strengths of electrical stimulation might have resulted in more prominent short latency factihtation' (Becker et al, 1987). This coincides with our results, i.e.…”

Section: Discussionsupporting

confidence: 91%

“…This was also true in human flexor reflexes. Becker et al (1987) elicited wrist muscle reflex with a background activity and suggested a recruitment of fast twitch motor units together with the background sustained contraction. These facts may suggest that the human jaw-opening reflex in response to oral receptors could work when the jaw is moving voluntarily.…”

Section: Discussionmentioning

confidence: 98%

“…Similar results were found in the human wrist muscle. Jenner & Stephens (1982) and Becker et al (1987) studied a segmented flexor refiex with mechanical and electrical stimulation. In their results, segmented excitatory responses were elicited with electrical stimulation.…”

Section: Discussionmentioning

confidence: 99%

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Human jaw‐opening muscle responses elicited by multiple‐site electrical stimulation

Yamada

Haraguchi

et al. 1990

J of Oral Rehabilitation

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Electrical stimuli were applied to subjects' upper and/or lower gingivae around the right canines; (i) during maintained relaxation of masticatory muscles; (ii) at an active opening position; (iii) while clenching in an incisal edge-to-edge contact (IEC) position; and (iv) at the wide-open position. Reflex responses of the suprahyoid and jaw-closing muscles were obtained using surface electrodes. The electrical stimulation produced segmented reflex excitation(s) in the suprahyoid muscle and conventional reflex excitation and/or inhibition in the jaw-closing muscles when some background activity was maintained in the muscle(s). The excitatory reflex in the suprahyoid muscle responded to multiple site electrical stimulation which was delivered on both the upper and lower jaw simultaneously rather than to single site stimulation. Also, the responses depended on the intensity of the electrical stimulation. In particular, stronger intensities resulted in longer latencies. The results support the suggestions in our previous studies with mechanical stimuli, i.e. that the human jaw-opening reflex can be obtained only when some background activity is maintained in the jaw openers, perhaps due to low threshold afferent input, and that spatial summation may be effective for the reflex.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 98%

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Human jaw‐opening muscle responses elicited by multiple‐site electrical stimulation

Yamada

Haraguchi

et al. 1990

J of Oral Rehabilitation

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“…Additionally, the only excitatory changes in EMG elicited by direct activation of cutaneous receptors, upon applying the stimulator probe to various areas of skin over the wrist and forearm, were small and delayed (> 60 ms). Thus, cutaneous afferents, although capable of exerting well-defined reflex actions upon FCR in man when stimulated electrically (Becker, Hayashi, Lee & White, 1986;Cody, Plant & Richardson, 1988b), made no substantial contribution in the present context. This leaves muscle receptors, in the stretched muscle, as the most probable origin of the afferent input responsible for the LL, as well as SL, response to tendon extension.…”

Section: Mechanisms Underlying Reflexes To Tendon Extensionmentioning

confidence: 77%

“…Additionally, the only excitatory changes in EMG elicited by direct activation of cutaneous receptors, upon applying the stimulator probe to various areas of skin over the wrist and forearm, were small and delayed (> 60 ms). Thus, cutaneous afferents, although capable of exerting well-defined reflex actions upon FCR in man when stimulated electrically (Becker, Hayashi, Lee & White, 1986;Cody, Plant & Richardson, 1988b) (Marsden, Merton & Morton, 1972) and group II (Matthews, 1984) reflex action; both group Ia and group II input, as shown in animal studies, can produce autogenetic excitation whereas the effects of tendon organ input are mainly inhibitory (for review see Baldiserra, Hultborn & Illert, 1981). The present data do not, however, allow any definite discrimination between the two groups of spindle afferents.…”

Section: Stretch-evoked Reflexes In Wrist Flexorsmentioning

confidence: 99%

Electromyographic reflexes evoked in human wrist flexors by tendon extension and by displacement of the wrist joint.

Cody

Plant

1989

The Journal of Physiology

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SUMMARY1. The electromyographic (EMG) reflexes evoked in the wrist flexor muscle, flexor carpi radialis (FCR), by percutaneous extension of its tendon and by forcible extension of the wrist joint have been studied. Reflexes were elicited during steadily maintained voluntary flexor contraction of 10% of each subject's maximum.2. Tendon extension, using 'ramp and hold' displacements, evoked fairly prolonged (ca 50 ms) increases in EMG activity. These responses were usually subdivided into two main excitatory peaks of respectively short (SL, ca 20 ms) and long (LL, ca 45 ms) latency. This pattern contrasted with that observed following brief tendon taps when only a single, SL peak was elicited.3. 'Stretch' reflexes evoked by 'ramp and hold' wrist extensions, as has been noted by numerous earlier investigators, were also protracted and comprised two main excitatory components. These responses resembled those produced by tendon extension both in their general form and in their behaviour upon altering the velocity of mechanical stimuli. Quantitatively, however, two main differences were evident. The reflexes evoked by wrist extension, including their SL and LL peaks, were generally somewhat larger. Additionally, when parameters of the two modes of stimulation were adjusted to elicit SL responses of equivalent amplitude, the LL responses elicited by tendon extension were regularly smaller and of shorter duration than those elicited by wrist extension.4. Termination of the two forms of mechanical stimulation, by releasing tendon or wrist extension, each elicited a SL reduction in EMG activity. Such troughs were more pronounced and more consistently observed upon release of wrist extension.5. Neither local anaesthesia of the skin overlying the flexor tendons at the wrist nor ischaemia of the hand and lower forearm produced any systematic modification of reflex response patterns. 6. It is concluded that intramuscular receptors (presumably muscle spindles) in FCR mediate both the SL and LL reflexes evoked in this muscle by extension of its tendon. Intramuscular receptors also seem certain to be very largely responsible for the EMG responses generated in this muscle by wrist extension.

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Vibration-evoked reciprocal inhibition between human wrist muscles

Cody

Plant

1989

Exp Brain Res

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Reciprocal inhibition of the voluntarily contracting wrist extensor (extensor carpi radialis, ECR) evoked by proprioceptive afferent input from the flexor (flexor carpi radialis, FCR), was studied in healthy human subjects. Vibration of the FCR tendon was used to elicit Ia-dominated afferent discharge whilst inhibition of ECR was assessed as the reduction in asynchronous, on-going EMG. A small early phase of inhibition (I1) was evident in 25% of trials. The latency (ca. 25 ms) of this component suggested that it was mediated by an Ia oligosynaptic. possibly 'classical' disynaptic, inhibitory pathway. A later and apparently separate phase of reduced activity (I2, ca. 40 ms) was, however, far more consistently observed (96% of trials) and of greater magnitude. The I2 component was usually followed, some 20 ms later, by a phase of elevated activity (E1, 72% trials). Reductions in simultaneously recorded net extensor torque commenced at about 60 ms following the onset of flexor tendon vibration, i.e. some 20 ms after the main I2 EMG component. These mechanical responses must have almost exclusively resulted from reciprocal inhibition of extensor EMG since vibration of the relaxed FCR evoked minimal excitatory flexor activity. The reflex pattern, in any individual subject, was relatively unaffected by altering the duration of the vibration train between one and nineteen cycles (125 Hz). This suggests that the entire response complex resulted largely from the initial afferent volley. The sizes of both the I1 and I2 reductions in ECR activity increased with increasing voluntary extensor contraction so that their depths remained constant proportions of background EMG. Very similar results were obtained when reciprocal inhibition of FCR was produced by vibration of the belly of ECR. Thus, reciprocal inhibition between wrist muscles is mainly expressed as a rather stereotyped, short duration reduction in EMG whose depth is determined by the pre-existing level of motor activity. Some functional implications of this form of reflex behaviour are discussed.

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Effect of cutaneous nerve stimulation on voluntary and stretch reflex electromyographic activity in wrist flexors in humans.

Cited by 9 publications

References 21 publications

Human jaw‐opening muscle responses elicited by multiple‐site electrical stimulation

Human jaw‐opening muscle responses elicited by multiple‐site electrical stimulation

Electromyographic reflexes evoked in human wrist flexors by tendon extension and by displacement of the wrist joint.

Vibration-evoked reciprocal inhibition between human wrist muscles

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