Motor reactions to perturbations of gait: proprioceptive and somesthetic involvement

Procházka, A.; Sontag, K.-H.; Wand, P.

doi:10.1016/0304-3940(78)90109-x

Cited by 67 publications

(51 citation statements)

References 10 publications

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“…servo. Indeed, may instances could be cited, where servo action would be most inappropriate, and has, in some cases, been shown to be overriden (Newsom, Davis & Sears, 1970;Prochazka, Sontag & Wand, 1978). However, it is equally clear, that segmental reflexes often act to impart to mammalian neuromuscular systems characteristics of response similar to those of servos (Crago, Houk & Hasan, 1976;Nichols & Houk, 1976;Ghez & Shinoda, 1978;Houk, 1979).…”

Section: Tendon Organ Dischargementioning

confidence: 99%

Tendon organ discharge during voluntary movements in cats.

Procházka¹,

Wand²

1980

The Journal of Physiology

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SUMMARY1. The discharge activity of tendon organ afferents was recorded during voluntary movements in cats.2. The eight tendon organ afferents in our sample all fired during isotonic movements involving active muscle shortening.3. Firing rates usually exceeded 100 sec', even up to the highest muscle shortening velocity observed, 1'8 resting lengths per second (lr/sec).4. We suggest that during voluntary, isotonic movements involving muscle shortening at velocities exceeding 02 Ir/sec, the net action of muscle afferents on homonymous motoneurones is often inhibition.5. These observations on tendon organs, taken together with previous findings on muscle spindles, indicate that in normal fast movements the role of the large muscle afferents is to signal dynamic functions of muscle length and force.

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Section: Tendon Organ Dischargementioning

confidence: 99%

Tendon organ discharge during voluntary movements in cats.

Procházka¹,

Wand²

1980

The Journal of Physiology

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“…For instance, mechanical stimulation of the foot dorsum during the swing phase of locomotion generates a coordinated reflex, the stumbling corrective reaction, in several leg muscles bilaterally allowing the perturbed limb to progress over the obstacle (Buford and Smith 1993;Forssberg 1979;Prochazka et al 1978;Wand et al 1980;Zehr and Stein 1999). In the stumbling corrective reaction, the ipsilateral leg is lifted over the obstacle while the contralateral leg supports the stimulated limb (i.e., crossed extensor reflex).…”

Section: Introductionmentioning

confidence: 99%

Short-Latency Crossed Inhibitory Responses in Extensor Muscles During Locomotion in the Cat

Frigon

Rossignol²

2008

Journal of Neurophysiology

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During locomotion, contacting an obstacle generates a coordinated response involving flexion of the stimulated leg and activation of extensors contralaterally to ensure adequate support and forward progression. Activation of motoneurons innervating contralateral muscles (i.e., crossed extensor reflex) has always been described as an excitation, but the present paper shows that excitatory responses during locomotion are almost always preceded by a short period of inhibition. Data from seven cats chronically implanted with bipolar electrodes to record electromyography (EMG) of several hindlimb muscles bilaterally were used. A stimulating cuff electrode placed around the left tibial and left superficial peroneal nerves at the level of the ankle in five and two cats, respectively, evoked cutaneous reflexes during locomotion. During locomotion, short-latency (ϳ13 ms) inhibitory responses were frequently observed in extensors of the right leg (i.e., contralateral to the stimulation), such as gluteus medius and triceps surae muscles, which were followed by excitatory responses (ϳ25 ms). Burst durations of the left sartorius (Srt), a hip flexor, and ankle extensors of the right leg increased concomitantly in the mid-to late-flexion phases of locomotion with nerve stimulation. Moreover, the onset and offset of Srt and ankle extensor bursts bilaterally were altered in specific phases of the step cycle. Short-latency crossed inhibition in ankle extensors appears to be an integral component of cutaneous reflex pathways in intact cats during locomotion, which could be important in synchronizing EMG bursts in muscles of both legs.

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“…In the cat, contact between the paw dorsum and an object during the swing phase of locomotion evokes a characteristic pattern of motoneuron activity that lifts the paw to clear the obstacle (Buford and Smith 1993;Forssberg 1979;Forssberg et al 1977;Prochazka et al 1978;Wand et al 1980). Studies in chronic spinal cats (Forssberg 1979;Forssberg et al 1977) indicate that the neuronal circuitry necessary to generate this functionally important reflex is contained within the lumbar spinal cord.…”

Section: Introductionmentioning

confidence: 99%

“…During the stumbling corrective reaction, knee flexors are activated, and there is a brief period in which ankle extensors are excited. This is followed by an increased and often prolonged flexion at the hip, knee, and ankle (Buford and Smith 1993;Forssberg 1979;Forssberg et al 1977;Pratt et al 1996;Prochazka et al 1978;Wand et al 1980). The same stimulation during the extension phase evokes another reflex, the stumbling preventive reaction.…”

Section: Introductionmentioning

confidence: 99%

Intracellular Analysis of Reflex Pathways Underlying the Stumbling Corrective Reaction During Fictive Locomotion in the Cat

Quevedo

Stecina²,

McCrea³

2005

Journal of Neurophysiology

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. Intracellular analysis of reflex pathways underlying the stumbling correction reaction during fictive locomotion in the cat. J Neurophysiol 94: 2053-2062. First published May 25, 2005 doi:10.1152/jn.00176.2005. In cat and humans, contact between an obstacle and the dorsum of the foot evokes the stumbling corrective reaction (reflex) that lifts the foot to avoid falling. This reflex can also be evoked by short trains of stimuli to the cutaneous superficial peroneal (SP) nerve in decerebrate cats during the flexion phase of fictive locomotion. Here we examine intracellular events in hindlimb motoneurons accompanying stumbling correction. SP stimulation delivered during the flexion phase excites knee flexor motoneurons at short latency [minimum excitatory postsynaptic potential (EPSP) latency 1.8 ms; mean 2.7 ms]. Although a similar short latency excitation occurs in ankle extensors (mean latency, 2.8 ms), recruitment is delayed until successive shocks in the stimulus train overcome the locomotor-related hyperpolarization of ankle extensors. In ankle flexor motoneurons, SP stimulation evokes an inhibition (mean latency, 2.7 ms) that briefly reduces or stops their firing during the flexion phase. There is a phase-dependent modulation of SP-evoked EPSP amplitude as well as latency during locomotion. However, the more obvious change in SP reflex pathways with the onset of fictive locomotion is the reduced inhibition of ankle extensor motoneurons and the increased inhibition of ankle flexors. These results show that the characteristic pattern of hindlimb motoneuron activation during SP nerve-evoked stumbling correction results from 1) di-and trisynaptic excitation of knee flexor and ankle extensor motoneurons; 2) increased inhibitory postsynaptic potentials in ankle flexors and a suppression of inhibition in extensors, 3) sculpting of the short-latency SP postsynaptic effects by motoneuron membrane potential, and 4) longer latency excitatory effects that are likely evoked by lumbar interneurons involved in the generation of fictive locomotion.

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Motor reactions to perturbations of gait: proprioceptive and somesthetic involvement

Cited by 67 publications

References 10 publications

Tendon organ discharge during voluntary movements in cats.

Tendon organ discharge during voluntary movements in cats.

Short-Latency Crossed Inhibitory Responses in Extensor Muscles During Locomotion in the Cat

Intracellular Analysis of Reflex Pathways Underlying the Stumbling Corrective Reaction During Fictive Locomotion in the Cat

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