Efferent discharges recorded from single skeletomotor and fusimotor fibres in man.

Ribot, E; Roll, Jean-Pierre; Vedel, J. P.

doi:10.1113/jphysiol.1986.sp016115

Cited by 93 publications

(53 citation statements)

References 63 publications

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“…They were sampled at 10 kHz. Contrary to our previous studies (Ribot et al 1986;Ribot-Ciscar et al 2000), the use of a highly sensitive photocell was not possible in the present one. Indeed, the movement amplitudes were incompatible with the very short distance (5 mm) between muscle tendon and transducer necessary for it to be sensitive to tiny displacements of the muscle tendon.…”

Section: Data Recordingscontrasting

confidence: 53%

Fusimotor Drive May Adjust Muscle Spindle Feedback to Task Requirements in Humans

Ribot-Ciscar¹,

Hospod²,

Roll³

et al. 2009

Journal of Neurophysiology

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Ribot-Ciscar E, Hospod V, Roll JP, Aimonetti JM. Fusimotor drive may adjust muscle spindle feedback to task requirements in humans. J Neurophysiol 101: 633-640, 2009. First published November 26, 2008 doi:10.1152/jn.91041.2008. The aim of the present study was to investigate whether the fusimotor control of muscle spindle sensitivity may depend on the movement parameter the task is focused on, either the velocity or the final position reached. The unitary activities of 18 muscle spindle afferents were recorded by microneurography at the common peroneal nerve. We compared in two situations the responses of muscle spindle afferents to ankle movements imposed while the subject was instructed not to pay attention to or to pay attention to the movement, both in the absence of visual cues. In the two situations, three ramp-and-hold movements were imposed in random order. In one situation, the three movements differed by their velocity and in the other by the final position reached. The task consisted in ranking the three movements according to the parameter under consideration (for example, slow, fast, and medium). The results showed that paying attention to movement velocity gave rise to a significant increase in the dynamic and static responses of muscle afferents. In contrast, focusing attention on the final position reached made the muscle spindle feedback better discriminate the different positions and depressed its capacity to discriminate movement velocities. Changes are interpreted as reflecting dynamic and static gamma activation, respectively. The present results support the view that the fusimotor drive depends on the parameter the task is focused on, so that the muscle afferent feedback is adjusted to the task requirements.

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Section: Data Recordingscontrasting

confidence: 53%

Fusimotor Drive May Adjust Muscle Spindle Feedback to Task Requirements in Humans

Ribot-Ciscar¹,

Hospod²,

Roll³

et al. 2009

Journal of Neurophysiology

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“…On the other hand, from observations in the high decerebrate locomoting cat it was deduced that static fusimotor firing was maintained at a tonic level while dynamic discharge was strongly modulated (Murphy, Stein & Taylor, 1984). Human microneurography has indicated changes in fusimotor activity during limb movements, but these changes have not been specified as static or dynamic (Vallbo, 1985;Ribot, Roll & Vedel, 1986). Clearly, there is a need for more data to be gathered on spindle behaviour in a variety of conditions and this paper presents results from some new experiments on jawclosing muscle spindles in the lightly anaesthetized cat.…”

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confidence: 99%

Fusimotor Influence on Jaw Muscle Spindle Activity during Swallowing‐Related Movements in the Cat

Taylor

Hidaka

Durbaba

et al. 1997

The Journal of Physiology

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The activity patterns of muscle spindle afferents in jaw‐closer muscles were studied during reflex swallowing movements in anaesthetized cats. Simultaneous records were made of the electromyogram (EMG) in masseter and anterior digastric muscles and of the unloaded jaw movements. The underlying patterns of fusimotor activity were deduced by comparing afferent discharges occurring during active swallowing with those occurring when exactly the same movements were imposed passively. The interpretation of spindle behaviour was greatly facilitated by characterizing the afferents according to the evidence for their contact with the various intrafusal muscle fibres, derived from testing with succinylcholine. It was also valuable to have two different types of afferent recorded simultaneously. There was clear evidence of fusimotor activity occurring during active jaw closing so as to oppose the spindle silencing. This effect was most marked in b2c‐type afferents (probably secondaries) and was therefore attributed to a modulation of static fusimotor discharge approximately in parallel with α‐activity. Afferents with evidence of bag1 fibre contacts (primaries) showed much greater sensitivity to muscle lengthening during active movement than when the movement was imposed. This difference was exaggerated when anaesthesia was deepened for the passive movements. This was interpreted as evidence for a higher level of dynamic fusimotor activity maintained during active movements than at rest. The results support the view that for a variety of active jaw movements, static fusimotor neurone firing is modulated roughly in parallel with α‐activity but leading it so as to counteract spindle unloading. Dynamic fusimotor neurone firing appears to be set at a raised level during active movements. Anaesthesia appears to depress activity in the α‐motoneurones more than in γ‐motoneurones.

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“…We found that target-guided contractions produced more 7-9 Hz coherence among MUs than self-guided contractions, which is consistent with the predicted effects of an increase in the magnitude or gain of afferent feedback. Such a change in afferent feedback and/or fusimotor activity might have stemmed from changes in the cognitive aspects of the task (Hospod et al 2007;Ribot et al 1986;Ribot-Ciscar et al 2000, changes in sympathetic drive (Abila et al 1985), or the change in force dynamics associated with error correction (Marsden et al 1970). Our results suggest that the absence/ presence of a target underlies changes in tremor previously associated with the general absence/presence of visual feedback.…”

Section: Discussionmentioning

confidence: 66%

Neural correlates of task-related changes in physiological tremor

Laine

Negro

Farina

2013

Journal of Neurophysiology

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Laine CM, Negro F, Farina D. Neural correlates of task-related changes in physiological tremor. J Neurophysiol 110: 170 -176, 2013. First published April 17, 2013 doi:10.1152/jn.00041.2013.-Appropriate control of muscle contraction requires integration of command signals with sensory feedback. Sensorimotor integration is often studied under conditions in which muscle force is controlled with visual feedback. While it is known that alteration of visual feedback can influence task performance, the underlying changes in neural drive to the muscles are not well understood. In this study, we characterize the frequency content of force fluctuations and neural drive when production of muscle force is target guided versus self guided. In the self-guided condition, subjects performed isometric contractions of the first dorsal interosseous (FDI) muscle while slowly and randomly varying their force level. Subjects received visual feedback of their own force in order to keep contractions between 6% and 10% of maximum voluntary contraction (MVC). In the targetguided condition, subjects used a display of their previously generated force as a target to track over time. During target tracking, force tremor increased significantly in the 3-5 and 7-9 Hz ranges, compared with self-guided contractions. The underlying changes in neural drive were assessed by coherence analysis of FDI motor unit activity. During target-guided force production, pairs of simultaneously recorded motor units showed less coherent activity in the 3-5 Hz frequency range but greater coherence in the 7-9 Hz range than in the self-guided contractions. These results show that the frequency content of common synaptic input to motoneurons is altered when force production is visually guided. We propose that a change in stretchreflex gain could provide a potential mechanism for the observed changes in force tremor and motor unit coherence.

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Efferent discharges recorded from single skeletomotor and fusimotor fibres in man.

Cited by 93 publications

References 63 publications

Fusimotor Drive May Adjust Muscle Spindle Feedback to Task Requirements in Humans

Fusimotor Drive May Adjust Muscle Spindle Feedback to Task Requirements in Humans

Fusimotor Influence on Jaw Muscle Spindle Activity during Swallowing‐Related Movements in the Cat

Neural correlates of task-related changes in physiological tremor

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