Evolving views on the internal operation and functional role of the muscle spindle.

Matthews, P. B. C.

doi:10.1113/jphysiol.1981.sp013931

Cited by 189 publications

(86 citation statements)

References 66 publications

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“…We would argue against this however, in that the parallelism between aand y-motoneurone firing is not at all constant and the term 'co-activation' though not usually clearly defined, implies a rather rigid linkage between the two systems. It has been shown repeatedly that there is in fact considerable opportunity for independence of action (see especially Matthews, 1972 (chapter 9);1981).…”

Section: Discussionmentioning

confidence: 99%

“…This leaves open the question of whether there may be some degree of separate control available over the bag2 and the chain fibres. Thus the interpretation offered for fusimotor action in reflex jaw movements is that the dynamic system provides 'parameter' control as visualized by Matthews (1981), while the static system generally provides a pattern of the intended movement, described as a 'temporal template'. This would mean that the static firing profile would generally resemble that of a activity, but the very different reflex connectivity of the two systems will cause frequent departures from a firm a-y co-activation (see also Appelberg et al 1983).…”

Section: Discussionmentioning

confidence: 99%

“…Neither is a simple co-activation of a-and fusimotor neurones (see Granit, 1970) adequate to explain the results, because there is much variability in the relation between spindle firing and muscle length changes. It has also become evident that static and dynamic fusimotor neurones have different central connexions and can indeed be selectively activated, thus making the general concept of 'a-y co-activation' an obvious over-simplification (see Matthews, 1981).…”

Section: Introductionmentioning

confidence: 99%

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Interpretation of fusimotor activity in cat masseter nerve during reflex jaw movements.

Gottlieb¹,

Taylor²

1983

The Journal of Physiology

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SUMMARY1. Simultaneous recordings were made from fusimotor axons in the central ends offilaments ofthe masseter nerve, and from masseter and temporalis spindle afferents in the mesencephalic nucleus of the fifth cranial nerve in lightly anaesthetized cats.2. Fusimotor and a-motor units in the masseter nerve were differentiated on the basis of their response to passive ramp and hold stretches applied to the jaw. Spindle afferents were identified as primary or secondary according to their dynamic index after administration of suxamethonium.3. The activity of a given fusimotor unit during reflex movements of the jaw followed one oftwo distinct patterns: so-called 'tonic' units showed a general increase in activity during a movement, without detailed relation to lengthening or shortening, while 'modulated' units displayed a striking modulation of their activity with shortening, and were usually silent during subsequent lengthening.4. Comparison of the simultaneously recorded fusimotor and spindle afferent activity suggests that modulated units may be representative ofa population of static fusimotor neurones, and tonic units of a population of dynamic fusimotor neurones.5. In these lightly anaesthetized animals, both primary and secondary spindle afferents showed increased firing during muscle shortening as well as during lengthening. This increase during shortening is not usually seen in conscious animals and reasons are given for the view that it is due to greater depression of a-motor activity than of static fusimotor activity during anaesthesia.6. The results are discussed in relation to the theories of 'a-y co-activation' and of 'servo-assistance'; and it is suggested that static fusimotor neurones provide a 'temporal template' of the intended movement, while dynamic fusimotor neurones set the required dynamic sensitivity to deviations from the intended movement pattern.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Interpretation of fusimotor activity in cat masseter nerve during reflex jaw movements.

Gottlieb¹,

Taylor²

1983

The Journal of Physiology

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“…Neurons were considered to respond to activated muscle proprioceptors when they (1) were sensitive to sinusoidal muscle stretching (Lundberg and Winsbury, 1960;Bianconi and van der Meulen, 1963;Brown et al, 1967;Matthews and Stein, 1969;Stuart et al, 1970;Mackie et al, 1998), showing a tight phase locking at the tested frequencies of 130 -135 Hz (Mackie et al, 1998); (2) produced spike bursting during stretching, a rapid drop in discharge on completion of the dynamic phase of stretching, and then a relatively slow drop during the holding phase (Matthews, 1933;Harvey and Matthews, 1961;Matthews, 1981;Edin and Vallbo, 1990); and (3) showed silenced firing during muscle shortening (stretch release) (Matthews, 1981;Edin and Vallbo, 1990;Grill and Hallet, 1995). It became clear during the first successful experiments in three distinct animals that cells responding in a 1:1 fashion to 130 -135 Hz muscular sinusoidal vibration also responded to manual muscle stretch (by flexing or extending the appropriated articulation), showing bursting discharges during the dynamic phase of stretching followed by a fall in discharge rate during holding and silenced firing during shortening.…”

Section: Methodsmentioning

confidence: 99%

Processing Afferent Proprioceptive Information at the Main Cuneate Nucleus of Anesthetized Cats

Leiras¹,

Velo²,

Martín-Cora³

et al. 2010

J. Neurosci.

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Medial lemniscal activity decreases before and during movement, suggesting prethalamic modulation, but the underlying mechanisms are largely unknown. Here we studied the mechanisms underlying proprioceptive transmission at the midventral cuneate nucleus (mvCN) of anesthetized cats using standard extracellular recordings combined with electrical stimulation and microiontophoresis. Dual simultaneous recordings from mvCN and rostroventral cuneate (rvCN) proprioceptive neurons demonstrated that microstimulation through the rvCN recording electrode induced dual effects on mvCN projection cells: potentiation when both neurons had excitatory receptive fields in muscles acting at the same joint, and inhibition when rvCN and mvCN cells had receptive fields located in different joints. GABA and/or glycine consistently abolished mvCN spontaneous and sensory-evoked activity, an effect reversed by bicuculline and strychnine, respectively; and immunohistochemistry data revealed that cells possessing strychnine-sensitive glycine receptors were uniformly distributed throughout the cuneate nucleus. It was also found that proprioceptive mvCN projection cells sent ipsilateral collaterals to the nucleus reticularis gigantocellularis and the mesencephalic locomotor region, and had slower antidromic conduction speeds than cutaneous fibers from the more dorsally located cluster region.The data suggest that (1) the rvCN-mvCM network is functionally related to joints rather than to single muscles producing an overall potentiation of proprioceptive feedback from a moving forelimb joint while inhibiting, through GABAergic and glycinergic interneurons, deep muscular feedback from other forelimb joints; and (2) mvCN projection cells collateralizing to or through the ipsilateral reticular formation allow for bilateral spreading of ascending proprioceptive feedback information.

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“…Alternatively, GDNF may regulate the physiological function of developing or adult MNs Martin-Caraballo and Dryer, 2002). Finally, MN-specific Ret KOs should provide a unique tool to study the function of ␥-MNs, which modulate muscle spindle sensitivity to stretch and firing rate (Matthews, 1981) and therefore regulate proprioceptive function during a variety of behavioral tasks such as locomotion (Murphy and Martin, 1993).…”

Section: Fusimotor Mns Depend On Gdnf Only During the Period Of Develmentioning

confidence: 99%

The Neurotrophic Effects of Glial Cell Line-Derived Neurotrophic Factor on Spinal Motoneurons Are Restricted to Fusimotor Subtypes

Gould¹,

Yonemura²,

Oppenheim³

et al. 2008

J. Neurosci.

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Glial cell line-derived neurotrophic factor (GDNF) regulates multiple aspects of spinal motoneuron (MN) development, including gene expression, target selection, survival, and synapse elimination, and mice lacking either GDNF or its receptors GDNF family receptor ␣1 (GFR␣1) and Ret exhibit a 25% reduction of lumbar MNs at postnatal day 0 (P0). Whether this loss reflects a generic trophic role for GDNF and thus a reduction of all MN subpopulations, or a more restricted role affecting only specific MN subpopulations, such as those innervating individual muscles, remains unclear. We therefore examined MN number and innervation in mice in which Ret, GFR␣1, or GDNF was deleted and replaced by reporter alleles. Whereas nearly all hindlimb muscles exhibited normal gross innervation, intrafusal muscle spindles displayed a significant loss of innervation in most but not all muscles at P0. Furthermore, we observed a dramatic and restricted loss of small myelinated axons in the lumbar ventral roots of adult mice in which the function of either Ret or GFR␣1 was inactivated in MNs early in development. Finally, we demonstrated that the period during which spindle-innervating MNs require GDNF for survival is restricted to early neonatal development, because mice in which the function of Ret or GFR␣1 was inactivated after P5 failed to exhibit denervation of muscle spindles or MN loss. Therefore, although GDNF influences several aspects of MN development, the survival-promoting effects of GDNF during programmed cell death are mostly confined to spindle-innervating MNs.

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Evolving views on the internal operation and functional role of the muscle spindle.

Cited by 189 publications

References 66 publications

Interpretation of fusimotor activity in cat masseter nerve during reflex jaw movements.

Interpretation of fusimotor activity in cat masseter nerve during reflex jaw movements.

Processing Afferent Proprioceptive Information at the Main Cuneate Nucleus of Anesthetized Cats

The Neurotrophic Effects of Glial Cell Line-Derived Neurotrophic Factor on Spinal Motoneurons Are Restricted to Fusimotor Subtypes

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