The restructuring of the efferent activity of the generator of scratching during the electrical activation of the descending systems

Rearrangement of the scratching generator activity evoked by phasic electrical stimulation of different descending systems has been investigated on decerebrated immobilized cats. This rearrangement heavily depends on the stimulation phase. Maximal increase of the scratching cycle duration by electrical stimulation of Deiters' nucleus, red nucleus and pyramidal tract takes place in the first half of an aiming phase. The electrical stimulation of structures mentioned above does not practically change duration of the scratching cycle in the second half of the aiming phase and at the beginning of the scratching phase. A maximal increase of the scratching cycle duration by electrical stimulation of reticular gigantocellular nucleus occurs in the second half of the aiming phase. The electrical activation of descending pathways during the aiming phase increases intensity of this phase and decreases intensity of the scratching phase. The electrical activation of descending pathways during the scratching phase increases its intensity and does not change practically the intensity of the aiming phase. Possible principles of the suprasegmental correction of the scratching generator activity are discussed.