Modular organization of human leg withdrawal reflexes elicited by electrical stimulation of the foot sole

Andersen, Ole Kæseler; Sonnenborg, Finn A.; Arendt‐Nielsen, Lars

doi:10.1002/(sici)1097-4598(199911)22:11<1520::aid-mus6>3.0.co;2-v

Cited by 121 publications

(83 citation statements)

References 27 publications

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“…In acute spinal cats, however, a reversed pattern of flexor inhibition or extensor excitation was observed under some conditions, indicating that there are also "private" paths apart from the flexion reflex (Holmqvist and Lundberg, 1961). Additionally, in animals (Levinsson et al, 1999) as well as the human lower limb (Hagbarth, 1960;Andersen et al, 1999), actions evoked by specific cutaneous afferents depended on the location of stimulation. Our results suggest that such alternative paths do not dominate during fatiguing contractions in humans.…”

Section: Discussionmentioning

confidence: 74%

Fatigue-Sensitive Afferents Inhibit Extensor but Not Flexor Motoneurons in Humans

Martin¹,

Smith²,

Butler³

et al. 2006

J. Neurosci.

161

159

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The role of group III and IV muscle afferents in controlling the output from human muscles is poorly understood. We investigated the effects of these afferents from homonymous or antagonist muscles on motoneuron pools innervating extensor and flexor muscles of the elbow. In study 1, subjects (n ϭ 8) performed brief maximal voluntary contractions (MVCs) of elbow extensors before and after a 2 min MVC of the extensors. During MVCs, electromyographic responses from triceps were evoked by stimulation of the corticospinal tracts [cervicomedullary motor evoked potentials (CMEPs)]. The same subjects repeated the protocol, but input from fatigue-sensitive afferents was prolonged after the fatiguing contraction by maintained muscle ischemia. In study 2, CMEPs were evoked in triceps during brief extensor MVCs before and after a 2 min sustained flexor MVC (n ϭ 7) or in biceps during brief flexor MVCs before and after a sustained extensor MVC (n ϭ 7). Again, ischemia was maintained after the sustained contractions. During sustained MVCs of the extensors, CMEPs in triceps decreased by ϳ35%. Without muscle ischemia, CMEPs recovered within 15 s, but with maintained ischemia, they remained depressed (by ϳ28%; p Ͻ 0.001). CMEPs in triceps were also depressed (by ϳ20%; p Ͻ 0.001) after fatiguing flexor contractions, whereas CMEPs in biceps were facilitated (by ϳ25%; p Ͻ 0.001) after fatiguing extensor contractions. During fatigue, inputs from group III and IV muscle afferents from homonymous or antagonist muscles depress extensor motoneurons but facilitate flexor motoneurons. The more pronounced inhibitory influence of these afferents on extensors suggests that these muscles may require greater cortical drive to generate force during fatigue.

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Section: Discussionmentioning

confidence: 74%

Fatigue-Sensitive Afferents Inhibit Extensor but Not Flexor Motoneurons in Humans

Martin¹,

Smith²,

Butler³

et al. 2006

J. Neurosci.

161

159

View full text Add to dashboard Cite

show abstract

“…The latency of the primary component of somatosensory cortical evoked potentials is about 40 ms (Dumitru, Kalantri, & Dierschke, 1991). The latency of the stretch reflex in the lower leg muscles is <50 ms for the short component, <100 ms for the middle component, and about 120 ms for the long component (Andersen, Sonnenborg, & Arendt-Nielsen, 1999;Diener & Dichgans, 1986). The postural responses observed in the present study might not be reflex responses, but instead might occur via the sensory reference system located in the supraspinal nervous system.…”

Section: Discussionmentioning

confidence: 99%

Postural Responses to Various Frequencies of Vibration of the Triceps Surae and Forefoot Sole during Quiet Standing

2015

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The purpose of this study was to determine the role of somatosensory input to the sensory reference system during quiet standing. Postural responses to vibration (0.5-mm amplitude, 1-60 Hz) applied to the Achilles tendons and forefoot soles were evaluated. Thirteen young healthy adults who showed backward-and forward-lean responses to vibration at high and low frequencies, respectively, participated as subjects. Backward-lean responses occurred at

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“…For example, many studies in human and reduced animal preparations have demonstrated that proprioceptive and cutaneous afferents can influence flexion reflex expression and patterned motor output during locomotion. [8][9][10][11][12][13][14][15][16][17] This raises the possibility that afferent activity induced by FES of muscle when used to generate the stance phase of gait could also influence flexion reflex pathways and indirectly influence the quality of swing achieved in FES-based walking.…”

Section: Introductionmentioning

confidence: 98%

Effects of electrically induced muscle contraction on flexion reflex in human spinal cord injury

Knikou

Conway

2005

Spinal Cord

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Study design: Flexion reflex study in motor complete human spinal cord injury (SCI). Objectives: To examine changes in the magnitude of the flexion reflex following functional electrical stimulation (FES) of the rectus femoris (RF) muscle. Setting: Bioengineering Unit, University of Strathclyde, Glasgow, Scotland, UK. Methods: The flexion reflex was evoked by electrical stimulation of the sural nerve, and was recorded in the tibialis anterior (TA) muscle. RF muscle conditioning stimulation was performed at 0.7, 1, and 2 times motor threshold ( Â MT) over a range of conditioning test intervals.Results: The incidence of the early component of the flexion reflex (o100 ms) was low, suggesting that this reflex component might be suppressed in SCI. The long latency flexion reflex component (4120 ms) was observed in all subjects during control conditions and following sensorimotor conditioning. FES applied to the RF muscle (above and below MT) in the main induced a significant early and long lasting depression of the long latency flexion reflex. Conclusion: The depression of the flexion reflex was a result of multisensory actions on flexion reflex pathways resulting from the direct and indirect (mechanical) consequences of electrically induced muscle contraction on cutaneous and muscle afferents. Our findings emphasize the importance of sensory feedback mechanisms in modulating flexion reflex excitability, and highlight the need for rehabilitation professionals to consider the central actions of FES-induced afferent feedback when incorporating FES into a rehabilitation program. Sponsorship: State Scholarships Foundation (IKY) of Hellas.Spinal Cord (2005) 43, 640-648.

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Modular organization of human leg withdrawal reflexes elicited by electrical stimulation of the foot sole

Cited by 121 publications

References 27 publications

Fatigue-Sensitive Afferents Inhibit Extensor but Not Flexor Motoneurons in Humans

Fatigue-Sensitive Afferents Inhibit Extensor but Not Flexor Motoneurons in Humans

Postural Responses to Various Frequencies of Vibration of the Triceps Surae and Forefoot Sole during Quiet Standing

Effects of electrically induced muscle contraction on flexion reflex in human spinal cord injury

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