[General functional state (tonus) of the brain and conditioned reflexes as the mechanisms of it's regulation].

The article is dedicated to P.S. Kupalov, due to his 120 Anniversary. P.S. Kupalov was the disciple of I.P. Pavlov and his nearest collaborator. Right after I.P. Pavlov, he was at the head of the Institute of Experimental Medicine in St-Petersburg, where he developed a number of new ideas, concerning conditioned reflexes. Thus, he discovered shortened conditioned reflexes--central mechanisms of regulation of general functional state of the brain, and he created, on the base of the studies of unlimited motor activity in animals using his own method of situational conditioned reflexes, the conception of situational conditioned reflexes. P.S. Kupalov found out a number of new explanations for development of experimental neuroses and determined their mechanisms, as well. He was the one among the first disciples of I.P. Pavlov, who indicated at the complex structural-functional organization of conditioned reflexes, and he played the great part for the creation of modern theory about the nature of behavior, based on conditioned reflexes. The most important theses of P.S. Kupalov's conception, which is of great cognitive significance at the moment, as well as some results of the studies by his disciples and followers, developing the ideas of P.S. Kupalov, are presented in the article.