Axonal conduction velocity and voluntary discharge properties of individual short toe extensor motor units in man.

Borg, Jörgen; Grimby, Lennart; Hannerz, Jan

doi:10.1113/jphysiol.1978.sp012266

Cited by 67 publications

(36 citation statements)

References 11 publications

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“…As described in an earlier study (Borg et al 1978) The isometric twitch tensions of the 'all or none' responses ranged from hardly measurable, i.e. 1 g, to 20 g. The maximum tensions were higher than those previously described for short toe extensor motor units in normal subjects but they were in accordance with findings after reinnervation (Sica & McComas, 1973).…”

supporting

confidence: 79%

“…Two of the subjects had increased muscle fibre density of the short toe extensor motor units due to collateral sprouting after repeated lesions to the terminal motor nerve twigs and muscle fibres one year earlier (see : Borg, Grimby & Hannerz, 1978). In these two subjects e.m.g.…”

Section: Methodsmentioning

confidence: 99%

“…It was shown in an earlier study that there is a relation between axonal conduction velocity and voluntary discharge pattern (Borg et al 1978).…”

mentioning

confidence: 99%

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Contraction time and voluntary discharge properties of individual short toe extensor motor units in man.

Grimby¹,

Hannerz²,

Hedman³

1979

The Journal of Physiology

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SUMMARY1. The contraction time and the voluntary discharge properties of forty-five short toe extensor motor units were studied in man.2. The contraction time of the individual motor unit was studied by using selective electrical nerve stimulation or by averaging the increase in force related to its electromyographic potential in tonic voluntary contraction.3. Both methods showed a range of contraction times from 40 to 90 ms.

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supporting

confidence: 79%

Section: Methodsmentioning

confidence: 99%

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Contraction time and voluntary discharge properties of individual short toe extensor motor units in man.

Grimby¹,

Hannerz²,

Hedman³

1979

The Journal of Physiology

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“…This happens because of accumulation of residual synaptic currents after the spike generation of a delay neuron. Coincidentally, a similar relationship between transmission delays and firing rates was observed in physiological recordings of voluntary discharge properties of extensor motor units in humans [29]. Fast spiking neurons were reported to exhibit smaller axonal delays and slower ones longer.…”

Section: A Limitationssupporting

confidence: 62%

Exploiting device mismatch in neuromorphic VLSI systems to implement axonal delays

Sheik

Chicca

Indiveri

2012

The 2012 International Joint Conference on Neural Networks (IJCNN)

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Abstract-Axonal delays are used in neural computation to implement faithful models of biological neural systems, and in spiking neural networks models to solve computationally demanding tasks. While there is an increasing number of software simulations of spiking neural networks that make use of axonal delays, only a small fraction of currently existing hardware neuromorphic systems supports them. In this paper we demonstrate a strategy to implement temporal delays in hardware spiking neural networks distributed across multiple Very Large Scale Integration (VLSI) chips. This is achieved by exploiting the inherent device mismatch present in the analog circuits that implement silicon neurons and synapses inside the chips, and the digital communication infrastructure used to configure the network topology and transmit the spikes across chips. We present an example of a recurrent VLSI spiking neural network that employs axonal delays and demonstrate how the proposed strategy efficiently implements them in hardware.

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“…We have previously studied the voluntary firing rates and recruitment order Grimby & Hannerz, 1977), axonal conduction velocity (Borg, Grimby & Hannerz, 1978) and contraction time (Grimby, Hannerz & Hedman, 1979) of single human motor units and found a continuum between two extreme types of motor units. One type were motor units with a maximum rate of about 30 Hz and a minimum rate for continuous firing of about 10 Hz which was low enough to be maintained voluntarily for apparently unlimited periods of time.…”

Section: Introductionmentioning

confidence: 99%

The fatigue and voluntary discharge properties of single motor units in man

Grimby

Hannerz

Hedman

1981

The Journal of Physiology

185

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1. The discharge properties of single motor units during prolonged maximal voluntary effort have been studied using electromyographic recordings, mainly in the short big toe extensor muscle but also in the anterior tibial muscle. 2. The required selectivity of the e.m.g. recordings was achieved in the short big toe extensor muscle after previous mechanical lesions to the terminal nerve twigs and muscle fibres and consequent collateral sprouting, and in the anterior tibial muscle with the use of a high impedance wire electrode. 3. During the first few hundred milliseconds of sustained maximal effort the motor units fired at rates ranging from about 30‐60 Hz, and the tension was the same as that obtained on electrical tetanization of the nerve to the toe extensor muscles above 50 Hz. 4. During prolonged maximal effort the firing rates and the proportion of motor units firing successively decreased. Motor units initially firing at 30 Hz continued to fire tonically but at 15‐20 Hz. Motor units initially firing at 60 Hz ceased to fire tonically but could still be made to discharge phasically. The period of time during which all motor units responded tonically could be increased from some seconds up to 20 sec by long‐term training. 5. Motor units with a limited endurance fired at a lower tension in the early than in the late stages of maintained contraction. 6. It is suggested that motoneurones innervating slow twitch muscle fibres respond continuously to prolonged voluntary drive at rates sufficient for full fusion but that the threshold of motoneurones innervating fast twitch muscle fibres increases so that they finally mainly fire phasically thus protecting the peripheral excitation and contractile mechanisms from excessive exhaustion.

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Axonal conduction velocity and voluntary discharge properties of individual short toe extensor motor units in man.

Cited by 67 publications

References 11 publications

Contraction time and voluntary discharge properties of individual short toe extensor motor units in man.

Contraction time and voluntary discharge properties of individual short toe extensor motor units in man.

Exploiting device mismatch in neuromorphic VLSI systems to implement axonal delays

The fatigue and voluntary discharge properties of single motor units in man

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