Recurrent inhibition of motoneurones prior to and during ramp and ballistic movements

Abstract

Recurrent inhibition directed to soleus motoneurones was studied in man prior to and during ramp and ballistic contractions of the triceps surae. There is no evidence for changes in recurrent inhibition prior to ballistic contractions and its increase during such contractions may result from a facilitation of Renshaw cells by the voluntary motor discharge reaching from them via recurrent collaterals. In the course of ramp contractions there is evidence for a control of Renshaw cell excitability from other sources: prior to the movement and at the beginning of the ramp there is a facilitation of Renshaw cells which shifts to an inhibition that peaks at the end of the ramp rising phase.