ABSTRACT
The phenomena of switching were extensively studied on dogs in E. A. Asratyan's laboratory with the use of the classical conditioned reflexes. In a dog, a classical (Pavlovian) conditioned reflex (CRI) had been established when a tone was always reinforced with the introduction of a small portion of acid solution into the dog's mouth. Two different avoidance CRIIs were trained in four dogs in the usual chamber. The training was conducted in separate series to each conditioned stimulus (CS). Each animal was trained to lift the right hindleg to the CS1 to avoid a nociceptive reinforcing stimulus which was either an electric shock or a puff-to-ear in various dogs. Then, in another series of sessions, the dog was trained to place its left foreleg on a platform to stimulus CS2 to avoid a nociceptive stimulus. hen the hypothalamic stimulation was substituted for food reinforcement, the dogs began to perform the previously trained alimentary CRII.
