Force-Sensitive Interneurons in the Spinal Cord of the Cat

Cleland, Corey L.; Rymer, William Z.; Edwards, Frank

doi:10.1126/science.7089586

Cited by 42 publications

(27 citation statements)

References 16 publications

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“…The effects of Pacinian corpuscles are also rare at such locations (Edgley & Jankowska, 1987 a, b). Free endings (Stacey, 1969;Cleland, Rymer & Edwards, 1982) and other mechanoreceptors (McLennan, 1972) appear on the other hand to have a much higher threshold to muscle stretch or muscle contraction.…”

Section: Discussionmentioning

confidence: 99%

Further evidence for synaptic actions of muscle spindle secondaries in the middle lumbar segments of the cat spinal cord.

Harrison

Jami

Jankowska

1988

The Journal of Physiology

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SUMMARY1. The aim of this study has been to investigate the receptor origin of postsynaptic actions evoked by group II muscle afferents in mid-lumbar segments of the cat spinal cord. The experiments tested the hypothesis that the afferents involved were the secondary endings of muscle spindles.2. Spindle afferents were activated by contractions of intrafusal muscle fibres which were induced by electrical stimulation of fusimotor axons in the distal parts of transected ventral roots by one to three stimuli at 150-500 stimuli/s. A separate series of experiments has shown that such stimuli are effective in activating a considerable proportion of muscle spindle secondaries when contractions of extrafusal muscle fibres are eliminated by differential fatigue of these fibres, provided that several fusimotor axons are stimulated simultaneously.3. Extracellular field potentials were recorded in the dorsal horn, at such locations where synaptic actions were evoked by electrical stimulation of group II but not group Ia muscle spindle or group Ib tendon organ afferents of pretibial flexors. Effects of activation of spindle afferents following stimulation of fusimotor axons were then compared with effects evoked by electrical stimulation of group II afferents of anterior tibial or extensor digitorum longus nerves and by small stretches of these muscles.4. Distinct field potentials were evoked by stimulation of ventral root fibres at all locations at which field potentials were obtained from group II afferents stimulated electrically. The latencies of these field po.,entials were in both cases shorter in the dorsal horn than in the ventral horn.5. The appearance of these field potentials was not related to contractions of extrafusal muscle fibres and was also observed when these contractions were practically eliminated. Furthermore, their threshold and similar dependence on a potentiating effect of two to three stimuli, as found for single secondaries, allow them to be attributed to secondary endings of muscle spindles.

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Section: Discussionmentioning

confidence: 99%

Further evidence for synaptic actions of muscle spindle secondaries in the middle lumbar segments of the cat spinal cord.

Harrison

Jami

Jankowska

1988

The Journal of Physiology

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“…For example, knee joint afferents can be found in the quadriceps and sartorius nerves (Freeman & Wyke, 1967 Other types of axon in the group II range include a small number of free endings 410 GROUP II FIELD POTENTIALS (Stacey, 1969;Cleland, Rymer & Edwards, 1982) and undefined mechanoreceptors (MacLennan, 1972). The latter are particularly common in the tibialis anterior nerve and may be present in other muscle nerves.…”

Section: Synaptic Linkage Of the Field Potentialsmentioning

confidence: 99%

Field potentials generated by group II muscle afferents in the middle lumbar segments of the cat spinal cord.

Edgley

Jankowska

1987

The Journal of Physiology

126

135

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SUMMARY1. A powerful projection from group II muscle afferents of hind-limb muscles to the 3rd, 4th and 5th segments of the lumbar spinal cord has been demonstrated by focal synaptic field potential recording.2. Field potentials were found at two locations: one in the dorsal horn (Rexed's laminae IV and V) and the other in the intermediate zone and ventral horn (Rexed's laminae VII and VIII). In the dorsal horn the field potentials were exceptionally large and were evoked only by group II afferents. At more ventral locations, they were smaller and were sometimes preceded by small field potentials evoked by group I afferents.3. At both locations field potentials could be evoked by stimulation of a number of hind-limb muscle nerves at strengths sufficient to activate group II afferents. However, some nerves consistently evoked more powerful effects than others and the largest potentials were from the nerves to quadriceps, sartorius and to the pretibial flexor muscles (tibialis anterior and extensor digitorum longus). Activation of articular afferents (from the knee joint nerve) or Pacinian corpuscle afferents (from the interosseous nerve) evoked small field potentials at some locations.4. In the dorsal horn the latency of the field potentials was so short that they must have been generated monosynaptically. Field potentials in the ventral horn had longer latencies, by 05-t10 ms, but they also appear to have been monosynaptically evoked by slowly conducting intraspinal collaterals. This conclusion is based primarily on the effects of intraspinal stimulation which was found to antidromically activate afferents with the appropriate latencies and thresholds.5. Evidence is presented that the dorsal and ventral field potentials are generated by afferents whose receptors can be activated by small (less than 100 /sm) muscle stretches.

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“…For example, it is even disputed whether the feedback of GTOs is positive or negative (e.g., Cleland et al 1982;Duysens and Pearson 1980;Prochazka et al 1997aProchazka et al , 1997b. Recent research provides evidence that the feedback of GTOs results in a positive force feedback (Donelan and Pearson 2004;Parkinson and McDonagh 2006;Pratt 1995;Van Doornik et al 2011).…”

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Control of position and movement is simplified by combined muscle spindle and Golgi tendon organ feedback

Kistemaker

Soest

Wong

et al. 2013

Journal of Neurophysiology

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Kistemaker DA, Van Soest AJ, Wong JD, Kurtzer I, Gribble PL. Control of position and movement is simplified by combined muscle spindle and Golgi tendon organ feedback. J Neurophysiol 109: 1126-1139, 2013. First published October 24, 2012 doi:10.1152/jn.00751.2012.-Whereas muscle spindles play a prominent role in current theories of human motor control, Golgi tendon organs (GTO) and their associated tendons are often neglected. This is surprising since there is ample evidence that both tendons and GTOs contribute importantly to neuromusculoskeletal dynamics. Using detailed musculoskeletal models, we provide evidence that simple feedback using muscle spindles alone results in very poor control of joint position and movement since muscle spindles cannot sense changes in tendon length that occur with changes in muscle force. We propose that a combination of spindle and GTO afferents can provide an estimate of muscle-tendon complex length, which can be effectively used for low-level feedback during both postural and movement tasks. The feasibility of the proposed scheme was tested using detailed musculoskeletal models of the human arm. Responses to transient and static perturbations were simulated using a 1-degree-of-freedom (DOF) model of the arm and showed that the combined feedback enabled the system to respond faster, reach steady state faster, and achieve smaller static position errors. Finally, we incorporated the proposed scheme in an optimally controlled 2-DOF model of the arm for fast point-to-point shoulder and elbow movements. Simulations showed that the proposed feedback could be easily incorporated in the optimal control framework without complicating the computation of the optimal control solution, yet greatly enhancing the system's response to perturbations. The theoretical analyses in this study might furthermore provide insight about the strong physiological couplings found between muscle spindle and GTO afferents in the human nervous system. sensorimotor control; tendon compliance; optimal control; perturbations IN THIS ARTICLE, we provide evidence that simple low-level spinal feedback using muscle spindles alone results in very poor control of joint position and movement. In short, this is because muscle spindles cannot detect the changes in muscletendon complex (MTC) length that occur as a consequence of tendon stretch. We propose that afferent signals from Golgi tendon organs (GTOs) can be seen as a proxy for tendon length and that, in combination with muscle spindles, they can be effectively used for low-level feedback during both postural and movement tasks. Before describing in more detail the specific aims of this study, we first provide an overview of the current view on the role of muscle spindles and GTOs relevant to this article.In recent years several theories have been postulated about how the central nervous system (CNS) controls position and movement. These theories all share the common premise that to control movements, the CNS must have information about the current state of the mu...

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Force-Sensitive Interneurons in the Spinal Cord of the Cat

Cited by 42 publications

References 16 publications

Further evidence for synaptic actions of muscle spindle secondaries in the middle lumbar segments of the cat spinal cord.

Further evidence for synaptic actions of muscle spindle secondaries in the middle lumbar segments of the cat spinal cord.

Field potentials generated by group II muscle afferents in the middle lumbar segments of the cat spinal cord.

Control of position and movement is simplified by combined muscle spindle and Golgi tendon organ feedback

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