Abstract
Changes in the activity of 44 neurons in the mesencephalic locomotor region and 38 neurons in the pontine inhibitory zone were recorded during stimulation of the gigantocellular reticular nucleus and the dorsal part of the oral reticular nucleus of the pons, which evokes inhibition of rigid tone in the hindlimbs of decerebrate rats. Decreases in muscle tone were always accompanied by decreases in the spike frequency of neurons in the mesencephalic locomotor region and increases in the activity of neurons in the pontine inhibitory zone. It is suggested that stimulation of the inhibitory parts of the brainstem simultaneously activates the reticulospinal inhibitory system, hyperpolarizing spinal alpha-motoneurons, and inhibits the neuron population of the mesencephalic locomotor region, which relates to the induction of locomotion and muscle tone.