Journal ArticleDOI
An evaluation of length and force feedback to soleus muscles of decerebrate cats.
J C Houk,J J Singer,M R Goldman +2 more
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This work has attempted to determine whether or not this regulation of force by signals from tendon organs is significant in decerebrate cats.Abstract:
IT IS NOW WELL KNOWN that contraction of a muscle is reflexly excited by responses of its spindle receptors to stretch (32, 34) and is reflexly inhibited by responses of its Golgi tendon organs to contraction (10, 31). Many experimental techniques have been used to confirm these observations (7, 12, 23). Nevertheless, the actual importance of each of these reflexes in the gradation of contraction remains obscure because of the lack of an experimental approach which is capable of estimating quantitatively their respective influences (39). Formerly it was believed by many that tendon organs responded and inhibited contraction on1 .y when muscular forces became excessive. Recent studies (19, 26) have cast doubt on this hypothesis by demonstrating for these receptors a much lower threshold to must ular contract ion than was previ not ouslv t .h assure ought. This find .ing alone does a con tinuo us regulation of muscular force by signals from tendon organs since impulses must be transmitted through one or two interneurons before they may inhibit homonymous motoneurons (7, 31). Studies have shown that these Ib pathways transmit impulses more effectively in spinal than in decerebrate cats (8). It is therefore likely that the gain of this reflex pathway is not constant but, rather, is subject to control by signals from various regions of the nervous system. For example, Ib pathways are facilitated by signals transmitted from the red nucleus (IS). As a result, the relative importance of tendon organs in the regulation of contraction would depend on the particular state of the experimental animal. We have attempted to determine whether or not this regulation of force is significant in decerebrate cats.read more
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Regulation of Stiffness by Skeletomotor Reflexes
TL;DR: This article reviews recent evidence indicating that the dominant opinion that stretch and unloading reflexes function to control the length of a muscle in opposition to changes in mechanical load is wrong and develops an alternative idea that neither muscle length nor force are regulated as individual vari ables, but that a property called stiffness is maintained relatively constant by skeletomotor reflexes.
References
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Journal ArticleDOI
Supraspinal control of the muscle spindles and its significance.
E. Eldred,R. Granit,P. A. Merton +2 more
Journal ArticleDOI
Properties of motor units in a homogeneous red muscle (soleus) of the cat.
TL;DR: It is found that the soleus, which is the object of this first study, is a homogeneous muscle, consisting wholly of one type of fiber, and the properties of soleus motoneurons clearly reflect its more uniform structure.
Journal ArticleDOI
Nature and significance of the reflex connections established by large afferent fibers of muscular origin.
Yves Laporte,David P. C. Lloyd +1 more
Journal ArticleDOI
On the Nature of Postural Reflexes
TL;DR: The “reflex standing” seen characteristically in the spinal animal, and exaggerated in the decerebrate animal, when analysed myographically is found to be a reflex contraction which is caused by stretch of the muscle itself, the “ stretch reflex ”.
Journal ArticleDOI
The reflex activity of mammalian small-nerve fibres.
TL;DR: The participation of the small-nerve fibres in reflex activity has not previously been investigated and can be finely graded by a process of facilitation, by the number and frequency of impulses reaching the spindle over individual small-NERV fibres.
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