The relative sensitivity to vibration of muscle receptors of the cat

Abstract

SUMMARY1. Longitudinal vibration was applied to the de-efferented soleus muscle of anaesthetized cats while recording the discharge of single afferent fibres from the proprioceptors within the muscle. Conditions were defined under which vibration can be used to excite selectively the primary endings of muscle spindles without exciting the secondary endings of muscle spindles or Golgi tendon organs.2. Frequencies of vibration of 100-500 c/s were used. The maximum amplitude of vibration which the vibrator could produce fell with increasing frequency; it was 250 ,t (peak to peak) for 100 c/s and 20 ,u for 500 c/s.3. Primary endings of muscle spindles were very sensitive to vibration. Most could be 'driven' to discharge one impulse for each cycle of vibration over the whole of the above range of frequencies, provided the initial tension was moderate (20-200 g wt.). The amplitude of vibration required to produce driving usually varied by less than a factor of two over the whole range of frequencies. The most sensitive endings could be driven by vibrations of below 10 t amplitude.4. Stimulation of single fusimotor fibres, whether static or dynamic fusimotor fibres, increased the sensitivity of primary endings to vibration. Contraction of the main muscle, produced by stimulating ac motor fibres, reduced the sensitivity of primary endings even when fusimotor fibres were also being stimulated.5. The secondary endings were very insensitive to longitudinal vibration and with the amplitudes available not one of twenty-five endings could be driven at 150 c/s or above; one ending could be driven at 100 c/s by vibration of 250 t amplitude. Stimulation of single fusimotor fibres, probably all of which were static fusimotor fibres, made them slightly more sensitive to vibration but none of them approached the sensitivity of the primary endings.6. The Golgi tendon organs were as insensitive as the secondary endings * Wellcome-Swedish travelling research fellow. Present address:

The Effect of Short-term Muscle Vibration on Knee Joint Torque and Muscle Firing Patterns during a Maximal Voluntary Isometric Contraction

“…In previous studies, muscle vibration has been associated with high activation of various skin and subcutaneous receptors; further, it has been reported that the la-afferent of the agonist muscle also cause a very high level of activity (Baik & Lim, 2006;Brown et al, 1967;Cordo et al, 1998;Roll & Vedel, 1982). In the study of Sabin (2003), it was confirmed that the lower extremity muscles were activated by vibratory stimulation during gait, which was attributed to vibration activating la-afferent of muscle spindle.…”

Tonic Vibration Reflex in Human and Monkey Subjects

“…5. The size of the reflex tension from TVR-f relation depends on the discharge frequency of the unitary EMG, which occurs according to the principle of the integer multiplication of original vibratory cyclic time.It has been demonstrated in cat musclethat primary spindle endings are much more sensitive to muscle vibration than secondary endings, their maximal response frequency being around 400Hz (GRANIT and HENATSCH, 1956;BESSOU and LAPORT, 1962;BIANCONI and VAN DER MEULEN, 1963;BROWN et al, 1967). It has also been reported by several authors that group Ia afferent discharges elicited by sinusoidal stretch activate the spinal motoneuron monosynaptically (MATTHEWS, 1966;HOMMA et al, 1967).…”

Processing Afferent Proprioceptive Information at the Main Cuneate Nucleus of Anesthetized Cats

“…Neurons were considered to respond to activated muscle proprioceptors when they (1) were sensitive to sinusoidal muscle stretching (Lundberg and Winsbury, 1960;Bianconi and van der Meulen, 1963;Brown et al, 1967;Matthews and Stein, 1969;Stuart et al, 1970;Mackie et al, 1998), showing a tight phase locking at the tested frequencies of 130 -135 Hz (Mackie et al, 1998); (2) produced spike bursting during stretching, a rapid drop in discharge on completion of the dynamic phase of stretching, and then a relatively slow drop during the holding phase (Matthews, 1933;Harvey and Matthews, 1961;Matthews, 1981;Edin and Vallbo, 1990); and (3) showed silenced firing during muscle shortening (stretch release) (Matthews, 1981;Edin and Vallbo, 1990;Grill and Hallet, 1995). It became clear during the first successful experiments in three distinct animals that cells responding in a 1:1 fashion to 130 -135 Hz muscular sinusoidal vibration also responded to manual muscle stretch (by flexing or extending the appropriated articulation), showing bursting discharges during the dynamic phase of stretching followed by a fall in discharge rate during holding and silenced firing during shortening.…”