Quantitative description of linear behavior of mammalian muscle spindles.

Poppele, R. E.; Bowman, R J

doi:10.1152/jn.1970.33.1.59

Cited by 299 publications

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“…From the limited data available (three units), it was not possible to identify the 'best' or most general mathematical function to predict spindle secondary firing. For the triceps surae secondaries, scaling the length signal gave good fits, whereas the the hamstring secondary data were better fitted with the use of the Poppele & Bowman (1970) secondary transfer function. Unfortunately very few spindle secondary afferents have been recorded from during normal movement, so the precise nature of the best spindle secondary model remains open.…”

Section: Discussionmentioning

confidence: 99%

“…These components were derived from the measured EMG signals, on the assumption that the EMG reflected the time course of á and ã activation. The second model was that of Poppele & Bowman (1970), describing spindle secondary afferents. Finally, we used the Houk & Simon (1967) transfer function describing tendon organ afferents.…”

Section: Mathematical Modellingmentioning

confidence: 99%

“…The speed of gait was markedly different in the two sets of data, so we analysed the units separately. Figure 3A shows the firing profile of unit 1 overlaid with a prediction obtained with the Poppele & Bowman (1970) spindle secondary transfer function: f = 0·59d(s + 0·4)(s + 11)Ï(s + 0·8) + 110, where f is the firing rate (s¢), 110 s¢ is the mean rate in the target profile, 0·59 is a scale factor chosen to give the optimal fit, d is muscle displacement (mm) and s is the Laplace operator. The very high mean firing rate of this afferent (110 s¢) is indicative of strong static fusimotor drive (Jami & Petit, 1978).…”

Section: Figure 1 Illustration Of Averaging Techniquementioning

confidence: 99%

“…3C: The data represent eight step cycles. Three models were used, the Poppele & Bowman (1970) group II model, and two ad hoc models of our own. The offset in each case (110 s¢) was the mean firing rate of the afferent in the step cycles analysed.…”

Section: Figure 1 Illustration Of Averaging Techniquementioning

confidence: 99%

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Ensemble firing of muscle afferents recorded during normal locomotion in cats

Procházka

Gorassini

1998

The Journal of Physiology

154

129

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The main purpose of this study was to collate population data on the firing characteristics of muscle afferents recorded chronically during normal stepping in cats. Ensemble firing profiles of forty‐seven muscle spindle and tendon organ afferents were compiled from stored data. The relationships between the firing profiles and the displacement and force signals were analysed with the help of mathematical models of the response characteristics of spindle primary and secondary afferents and tendon organs. Whereas the firing of hamstring spindle afferents could be predicted with reasonable accuracy from the length and velocity signals alone, the firing profiles of triceps surae spindle afferents deviated from the predicted profiles, particularly during electromyogram (EMG) activity. This indicated that the components of fusimotor action linked to extrafusal muscle activity were significant in triceps surae, possibly because this muscle is more strongly recruited in the cat step cycle. From the limited data available, it was not possible to identify the ‘best’ or most general mathematical function to predict spindle secondary firing. In the two triceps surae spindle secondary units studied, firing was well predicted by using the simplest possible model, rate proportional to displacement, whereas in the hamstring spindle secondary data, a more complex linear transfer function was needed. The results of modelling the spindle secondary data were consistent with a modest amount of phasic, static fusimotor action linked to EMG activity. The averaged ensemble of tendon organ afferent activity from the triceps surae gave predictions of whole‐muscle force that agreed well with separate triceps force measurements in normal cat locomotion. This supports the idea that ensembles of tendon organ afferents signal whole‐muscle force. Our overall conclusion is that to a first approximation, large muscle afferents in the cat hindlimb signal muscle velocity, muscle length and muscle force, at least in movements of the speed and amplitude seen in locomotion.

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Section: Discussionmentioning

confidence: 99%

Section: Mathematical Modellingmentioning

confidence: 99%

Section: Figure 1 Illustration Of Averaging Techniquementioning

confidence: 99%

Section: Figure 1 Illustration Of Averaging Techniquementioning

confidence: 99%

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Ensemble firing of muscle afferents recorded during normal locomotion in cats

Procházka

Gorassini

1998

The Journal of Physiology

154

129

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“…Small movements and forces are strongly dependent on peripheral inputs perhaps in part due to cutaneous and muscle receptors exhibiting their greatest sensitivity to small amplitude input signals (Goodwin et al, 1975;Knibestol, 1975;Knibestol and Vallbo, 1970;Matthews and Stein, 1969;Poppele and Bowman, 1970). The production of speech is dominated by small forces and fine adjustments in position (Barlow and Muller, 1991;Barlow and Rath, 1985;Muller et al, 1985).…”

Section: Introductionmentioning

confidence: 99%

Modulation of the trigeminofacial pathway during syllabic speech

Estep

Barlow

2007

Brain Research

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The human orofacial system is richly endowed with low threshold, slowly adapting mechanoreceptors that respond to self-generated movements and external loads. The functional linkage between these afferents and the recruitment of motor units in the lower face during the dynamics of speech is unknown. Mechanically evoked activity in the orbicularis oris muscles was studied in young human female adults (N=10) during a lip force recruitment task associated with the repetition of the nonsense speech utterance "ah-wah." This speech task involved the recruitment of perioral motor units against an elastic load. A skin contactor probe coupled to a servo-controlled linear motor delivered punctate ipsilateral mechanical inputs (25 ms duration, 1800 μm displacement) to the glabrous surface of the upper lip in order to index the modulation and specificity of the compound trigeminofacial response as a function of speech force recruitment threshold (Ft). Modulation of the early (Ft = 0.2N) and later (Ft = 1.0N) components of the evoked perioral response was found at the two force thresholds. Beginning at approximately 60 ms post-stimulus, a significant suppression response was found among lower lip EMG recording sites and its magnitude was greatest when the mechanical perturbation occurred during the early phase of lip force recruitment. Variation in the lip force trajectories was manifest by a greater difference in net interangle force associated with lip perturbations indexed to the early Ft. This was interpreted to reflect the operation of a feedforward mechanism which may play a more significant role during an evolving speech action. Thus, the application of servo-controlled mechanosensory inputs effectively indexed the excitability of the facial motor nucleus during production of a simple speech phrase. Future studies are needed to explore mechanisms of short-term adaptation and trigeminofacial modulation during propositional speech in health and disease.

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Muscle Sensory Receptors

Roatta

Passatore

2006

Wiley Encyclopedia of Biomedical Engineering

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The central nervous system (CNS) obtains information on whatever occurs in the muscles (i.e., mechanical and chemical changes) through sensory receptors located within muscles and joints, as well as in the portion of skin deformed by the motion. Several types of sensory receptors lie within skeletal muscles. (1) The very sensitive muscle spindles monitor muscle length and send this information to the CNS via the fastest conducting afferent nerve fibers in the body. (2) Golgi tendon organs are located in the musculo‐tendinous junctions and provide information about muscle force. (3) Free nerve endings with slow‐conducting, thinly myelinated or unmyelinated nerve afferents are sensitive to mechanical, chemical, and nociceptive stimuli. The description of the specific features and peculiarities of each of these receptor types is preceded by a brief overview of receptors in general, particularly about basic processes that take place in the receptive terminal (i.e., the transduction of the stimulus and the encoding of information into neural signals that are self‐regenerating) that can be transferred for long distances without decrement. In addition, a brief description of afferent nerve fibers carrying this information, as well as a description of the relationship between stimulus and sensation, will follow. Then, most of the chapter is devoted to the muscle spindle, which is justified by the anatomical and functional complexity and the relevance of this receptor in several body functions. A few models are presented concerning different aspects of the muscle spindle receptive function, and a brief reference is made to its involvement in the myotatic reflex, motor control, and high‐level body functions.

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Quantitative description of linear behavior of mammalian muscle spindles.

Cited by 299 publications

References 0 publications

Ensemble firing of muscle afferents recorded during normal locomotion in cats

Ensemble firing of muscle afferents recorded during normal locomotion in cats

Modulation of the trigeminofacial pathway during syllabic speech

Muscle Sensory Receptors

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