[Formation of reverse conditioned connections during unrestrained behavior]

Reactions achieved by the mechanism of backward connection were studied in unrestrained dogs with acoustic stimuli preceded by an alimentary unconditioned reflex: a 300 c/s acoustic stimulus was paired with feeding from the left feeding trough and 1000 c/s stimulus--with the right feeding trough. A certain dynamics was observed in the manifestation of these reactions. As the number of tests increased, the number of specific reactions diminished, while non-specific reactions and reactions of running to the door appeared. Acute extinction of the running reflex to the sound of the feeding trough has been shown that the dynamics of reactions to the later is the same as in tests to the tone. Proceeding from this, it may be assumed that the evolution of backward connections manifestation is based on extinctive inhibition which develops in consequence of non-reinforcement of conditioned stimuli in the tests on backward connection formation.