Function of the spindle dynamic response in stiffness regulation—a predictive mechanism provided by non-linear feedback
Autogenetic reflex responses that act to regulate muscle stiffness are initiated too soon and are too large to be explained solely on the basis of linear feedback from muscle spindle receptors and Golgi tendon organs. In this article we present several lines of evidence that the unexpected efficacy is due to the unique non-linear response properties of primary endings. Several of these non-linear features of spindle dynamic responses are well matched to assist in the maintenance of stiffness during the transient phases of response to muscle stretch and release. As a consequence of these spindle and muscle properties, appropriate reflex actions can actually occur in advance of the failures in stiffness for which they provide compensation. This result is interpreted to mean that the system is endowed with a predictive mechanism.
KeywordsMuscle Force Soleus Muscle Reflex Action Motor Servo Transient Phase
Unable to display preview. Download preview PDF.
- Crago, P. E., Houk, J. C. and Hasan, Z. (1976). Regulatory actions of the human stretch reflex, J. Neurophysiol., 30, 925–935Google Scholar
- Hasan, Z. and Houk, J. C. (1975). The transition in the sensitivity of spindle receptors that occurs when the muscle is stretched more than a fraction of a millimeter, J. Neurophysiol., 38, 673–689Google Scholar
- Houk, J. C. (1978a). A two-stage model of neural processes controlling motor output. In Cybernetics 1977 (edited by G. Hauske and E. Butenandt), Munich and Vienna, Oldenbourg Verlag, 35–46Google Scholar
- Houk, J. C. (1978b). Participation of reflex mechanisms and reaction-time processes in the compensatory adjustments to mechanical disturbances. In Progress in Clinical Neurophysiology, Vol. 4: Cerebral Motor Control in Man: Long Loop Mechanisms (edited by J. E. Desmedt), Basel, Karger, 193–215Google Scholar
- Houk, J. C. (1980). Homeostasis and control principles. In Medical Physiology, Fourteenth Edition (edited by V. B. Mountcastle), Vol. 2, St. Louis, Mosby, 246–270Google Scholar
- Houk, J. C., Crago, P. E. and Rymer, W. Z. (1980). Functional properties of the Golgitendon organs. In Prog. Clin. Neurophysiol., Vol. 8: Spinal and Supraspinal Mechanisms of Voluntary Motor Control and Locomotion (edited by J. E. Desmedt) Basel, Karger, 33–43Google Scholar
- Houk, J. C., Rymer, W. Z. and Crago, P. E. (1977). Complex velocity dependence of the electromyographic component of the stretch reflex, Proc. XXVII Int. Cong. Physiol. Sci., ParisGoogle Scholar
- Houk, J. C., Rymer, W. Z. and Crago, P. E. (1981). Nature of the dynamic response and its relation to the high sensitivity of muscle spindles to small changes in length, this publicationGoogle Scholar
- Matthews, P. B. C. (1972). Mammalian Muscle Receptors and Their Central Actions, London, ArnoldGoogle Scholar
- Nichols, T. R. (1974). Soleus muscle stiffness and its reflex control (Ph.D. thesis), Cambridge, Harvard UniversityGoogle Scholar
- Nichols, T. R. and Houk, J. C. (1976). The improvement in linearity and the regulation of stiffness that results from the actions of the stretch reflex, J. Neurophysiol., 39, 119–142Google Scholar