Kinaesthetic role of muscle afferents in man, studied by tendon vibration and microneurography

Abstract

The characteristics of vibration-induced illusory joint movements were studied in healthy human subjects. Unseen by the subject, constant frequency vibration trains applied to the distal tendon of the Triceps or Biceps induced an almost constant velocity illusory movement of the elbow whose direction corresponded to that of a joint rotation stretching the vibrated muscle. Vibration trains of the same duration and frequency applied alternatively to the Biceps and Triceps evoked alternating flexion-extension illusory movements. During successive application of vibration trains at frequencies from 10 to 120 Hz, the perceived velocity of the illustory movements increased progressively from 10 to 70-80 Hz, then decreased from 80 to 120 Hz. The maximal perceived velocity was three times higher during alternating vibration of the Biceps and Triceps than during single muscle stimulation. Unit activity from 15 muscle spindle primary endings and five secondary endings located in Tibialis anterior and Extensor digitorum longus muscles were recorded using microneurography in order to study their responses to tendon vibration and passive and active movements of the ankle. Primary endings were all activated by low amplitude tendon vibration (0.2-0.5 mm) previously used to induce illusory movements of the elbow. The discharge of some was phase-locked with the vibration cycle up to 120 Hz, while others responded one-to-one to the vibration cycle up to 30-50 Hz, then fired in a sub-harmonic manner at higher frequencies. Secondary endings were much less sensitive to low amplitude tendon vibration. Primary and secondary ending responses to ramp and sinusoidal movements of the ankle joint were compared. During the movement, the primary ending discharge frequency was almost constant, while the secondary ending activity progressively increased. During ankle movements the primary ending discharge appeared mainly related to velocity, while some secondary activities seemed related to both movement velocity and joint angle position. Muscle spindle sensory ending responses to active and passive ankle movements stretching the receptor-bearing muscle (plantar flexion) were qualitatively and quantitatively similar. During passive reverse movements (dorsiflexion) most of the sensory endings stopped firing when their muscle shortened. Active muscle shortening (isotonic contraction) modulated differently the muscle spindle sensory ending discharge, which could stop completely, decrease or some times increase during active ankle dorsiflexion. During isometric contraction most of the muscle spindle sensory endings were activated. The characteristics of the vibration-induced illusory movements and the muscle spindle responses to tendon vibration and to active and passive joint movements strengthened the possibility of the contribution of primary endings to kinesthesia, as suggested by several previous works...

Ankle proprioception is not targeted by exercises on an unstable surface

“…We think this choice is justifiable for two reasons. First, results in microneurography studies have demonstrated a major role of muscle spindles in proprioception (Cordo et al 1995;Goodwin et al 1972a;Roll and Vedel 1982) and muscle spindles are the primary sensory resource of information for maintaining balance during upright stance . Second, anesthetizing joint receptors only results in an increased positioning error in passive repositioning (Konradsen et al 1993).…”

“…Muscle spindles play a major role in proprioception (Cordo et al 1995;Goodwin et al 1972a;Roll and Vedel 1982). In studies on the role of proprioception in standing, vibration is used to analyze the relative contribution of a peripheral proprioceptive signal to the total motor output.…”

“…Vibration induces a bias into the muscle spindle output. The vibrated muscle is usually perceived to be longer than it actually is (Cordo et al 2005;Goodwin et al 1972b;Roll and Vedel 1982). This lengthening illusion under vibration will cause corrective displacement of the center of mass, related to the amount in which the central nervous system uses these signals for postural control.…”

Proprioceptive use and sit-to-stand-to-sit after lumbar microdiscectomy: The effect of surgical approach and early physiotherapy

“…Local muscle vibration was used to investigate the role of proprioception in postural control. Muscle vibration (60 Hz, 0.5 mm) is a powerful stimulus of muscle spindle Ia afferents, evoking an illusion of muscle lengthening (Cordo et al, 2005;Roll and Vedel, 1982). When the central nervous system uses proprioceptive signals of the vibrated muscles for postural control, this causes a directional corrective center of pressure displacement.…”

Muscular proprioception contributes to the control of interceptive actions.

“…Tendon vibration offers a means of achieving this end, since it is known to specifically activate muscular proprioception. Indeed, most primary endings respond in a one-to-one manner to a low amplitude vibratory stimulus for frequencies between 1 and 100 Hz (Roll & Vedel, 1982). Such responses of Ia muscle spindle afferents are well known to evoke illusory sensation of movement (Goodwin, McCloskey, & Matthews, 1972).…”