Reflex Activation of the Soleus Muscle of the Decerebrate Cat by Vibration

Abstract

THE primary afferent ending of the mammalian muscle spindle is highly sensitive to vibration^1–4. In the presence of fusimotor activity it may discharge an impulse on each cycle of vibration applied to the muscle tendon, for vibrations of frequencies up to 300–400/sec and of amplitudes of a fraction of a mm (refs. 2 and 4). In the decerebrate cat, maintained stretch of an extensor muscle usually evokes from it a prolonged reflex contraction–the classical stretch reflex⁵. This reflex is generally believed to depend on the excitation of the primary endings of the spindle by the stretching of the muscle. Thus, it might be anticipated that vibration would also evoke a ‘stretch reflex’ in the decerebrate cat. The present experiments show that it does, indeed, do so.