Tendon organ firing during active muscle lengthening in awake, normally behaving cats.

Appenteng, Kwabena; Procházka, A.

doi:10.1113/jphysiol.1984.sp015323

Cited by 50 publications

(15 citation statements)

References 17 publications

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“…The role of Golgi tendon organs in mediating the effects of viscous loads is uncertain. These receptors are exquisitely sensitive to changes in torque (Binder and Osborn, 1985;Houk and Henneman, 1967) and undoubtedly have a role in maintaining static postures; however, their role in active movement is far from clear (Appenteng and Prochazka, 1984). A possible parallel exists between the results of the present experiments and those of Hollingworth (1909).…”

Section: Discussionsupporting

confidence: 75%

Kinematics and end-point control of arm movements are modified by unexpected changes in viscous loading

Sanes¹

1986

J. Neurosci.

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These experiments were undertaken to evaluate whether the kinematics and end-point control of learned movements were affected by changes in dynamic loads or were determined largely by centrally specified motor programs. Human subjects performed flexion movements about the wrist in a discrete visual tracking task for a range of movement sizes. For some movements, viscosity was increased at movement onset. When the viscous load opposed movement unexpectedly, subjects initially overshot the intended target for all movement sizes, but only for the smaller movements did the overshoot persist. Unexpected introduction of heavier loads was more effective in inducing these behavioral changes; the lightest loads did not alter end-point positioning. When subjects had visual guidance about performance when load changes occurred, the effect of the unexpected occurrences of viscous loads was diminished, suggesting that subjects rapidly adjusted their movement strategy, depending on task demands and performance. The movement responses were mediated by short-latency and long-duration muscle responses triggered by the change in viscous loading. Although the triggered muscle responses were larger when the loads were encountered during performance of large, in comparison to small, movements, smaller muscle responses affected small movements more than large triggered responses did large movements. This suggests that triggered muscle responses are compensatory in certain movement situations but disruptive in others. In addition, these findings demonstrated that dynamic loads especially affect the kinematics and end-point control of smaller movements, suggesting that kinesthetic inputs and central motor commands interact so subjects may achieve accurate positioning for certain classes of movements.Several recent studies of motor control in patients with sensory loss have described impairments of movement accuracy as a result of viscous-load changes occurring during movement (Day and Marsden, 1982;Nam et al., 1984;Rothwell et al., 1982a;Sanes et al., 1985). The reason for the use of viscous loads (as compared to springs or weights) in these studies was that viscous loads acted during displacement but not during absence of movement. Thus, if a subject is to displace the wrist from one angle to another at a fixed angular velocity, an unexpected change of viscosity will require changed muscular output during the displacement between the starting position and the terminal

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Section: Discussionsupporting

confidence: 75%

Kinematics and end-point control of arm movements are modified by unexpected changes in viscous loading

Sanes¹

1986

J. Neurosci.

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“…It was suggested that they were tendon organ afferents because their instantaneous firing frequency was modulated in a sawtooth fashion, which Larson et al believed to be due to the rapid changes in tension brought about by the intermittant contraction of a single motor unit inserting into the receptor. Appenteng and Prochazka 104 have shown subsequently that tendon organ afferents from ankle extensor muscles do not fire in such a manner. Only IA afferents do this, which suggests that the units classified as tendon organs by Larson et al may have been a subpopulation of spindle primary afferents.…”

Section: Golgi Tendon Organs and Other Afferentsmentioning

confidence: 96%

Mastication and its Control by the Brain Stem

Lund

1991

Critical Reviews in Oral Biology & Medicine

528

384

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This review describes the patterns of mandibular movements that make up the whole sequence from ingestion to swallowing food, including the basic types of cycles and their phases. The roles of epithelial, periodontal, articular, and muscular receptors in the control of the movements are discussed. This is followed by a summary of our knowledge of the brain stem neurons that generate the basic pattern of mastication. It is suggested that the production of the rhythm, and of the opener and closer motoneuron bursts, are independent processes that are carried out by different groups of cells. After commenting on the relevant properties of the trigeminal and hypoglossal motoneurons, and of internuerons on the cortico-bulbar and reflex pathways, the way in which the pattern generating neurons modify sensory feedback is discussed.

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“…Even during shortening contractions, tendon organs faithfully transduce force increments during unfused contractions (135,160). Tendon organ frequency sometimes "steps" up, presumably reflecting recruitment of a new motor unit (e.g., 7,64,319). The conventional wisdom asserted that even if a single tendon organ did not respond proportionally to maintained force, the ensemble input from a muscle's complement of tendon organs would mirror active force in the tendon.…”

Section: Tendon Organ Aherentsmentioning

confidence: 97%