[Mechanism of switching over simple and systemic conditioned reflexes to time in animals]

Switching over of simple reflexes and of a system of reflexes to "pure" time was studied on 12 rabbits, 2 dogs and one monkey. Instrumental conditioned reflexes (pulling a ring or pressing a pedal) were elaborated in response to 5; 4, 2 and 1.5 minutes time intervals; a system of conditioned reflexes was elaborated to different time intervals: 1.5--2.5--3.5 min and 4--2 min. Switching over agents were a metronome (300 beats/min), noise of a ventilator plus light of an electrical bulb, as well as different quantities or qualities of alimentary reinforcement. Turning in of the one and turning out of the other agents caused switching over of the food-procuring activity from one rhythm to another. The mechanisms of this complex form of integrative brain activity are discussed.