Fusimotor after-effects on bag₁ contraction

Abstract

Stimulation of fusimotor axons leaves persistent after-effects which enhance the responses of primary endings to stretch (Brown, Goodwin and Matthews, 1969; Baunann, Emonet-Dénand and Hulliger, 1983). We have used the responses of primary endings to test stimulation of dynamic axons during slow ramp stretch of cat soleus muscle as an index of after-effects influencing the bag fibre (Emonet-Dénand, Hunt and Laporte, in press). Conditioning stimulation of a dynamic axon causes a large increase in the response of a primary ending to subsequent brief stimulation of the sane axon during a ramp stretch. Frequencygrams to low frequency test stimulation (2–3/sec) of a dynamic axon shows a large increase in the response to individual stimuli during the after-effect.