Functional properties of human muscle spindles
| Autor: | Thomas P. Knellwolf, Vaughan G. Macefield |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
Motor Neurons Gamma Physiology Fusimotor Neurons General Neuroscience Action Potentials Microneurography Biology Proprioception 03 medical and health sciences 030104 developmental biology 0302 clinical medicine Human muscle Animals Humans Neurons Afferent Muscle Spindles Neuroscience 030217 neurology & neurosurgery Muscle Contraction |
| Zdroj: | Journal of Neurophysiology. 120:452-467 |
| ISSN: | 1522-1598 0022-3077 |
| DOI: | 10.1152/jn.00071.2018 |
| Popis: | Muscle spindles are ubiquitous encapsulated mechanoreceptors found in most mammalian muscles. There are two types of endings, primary and secondary, and both are sensitive to changes in muscle length and velocity, with the primary endings having a greater dynamic sensitivity. Unlike other mechanoreceptors in the somatosensory system, muscle spindles are unique in possessing motor innervation, via γ-motoneurons (fusimotor neurons), that control their sensitivity to stretch. Much of what we know about human muscles spindles comes from studying the behavior of their afferents via intraneural microelectrodes (microneurography) inserted into accessible peripheral nerves. We review the functional properties of human muscle spindles, comparing and contrasting with what we know about the functions of muscle spindles studied in experimental animals. As in the cat, many human muscle spindles possess a background discharge that is related to the degree of muscle stretch, but mean firing rates are much lower (~10 Hz). They can faithfully encode changes in muscle fascicle length in passive conditions, but higher level extraction of information is required by the central nervous system to measure changes in muscle length during muscle contraction. Moreover, although there is some evidence supporting independent control of human muscle spindles via fusimotor neurons, any effects are modest compared with the clearly independent control of fusimotor neurons observed in the cat. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|