[Changes in the excitability of motor neurons and synaptic effects on them during the formation of a locomotor generator in the cat].

It is shown on decorticated (high-decerebrated) and spinal cats and on spinal cats injected with DOPA that the activation of the spinal locomotor generator is accompanied by an increase of the extensor and a decrease of the flexor motoneurons' excitability, an increase of the recurrent and reciprocal Ia inhibition, a decrease of Ib and flexor reflex afferent influences on motoneurons. The possible physiological role of changes in tuning of the spinal segmental apparatus in the generation of the locomotor rhythm is discussed.