Cats with chronic electrodes in the inferior colliculus received paired presentations of a weak (CS) and a strong (US) electrical stimulus delivered through the same electrode. After 140-200 such pairings, the weaker stimulus was able to elicit a close approximation to the unconditioned motor response elicited by the stronger stimulus. The response eventually elicited by the weaker stimulus was seen to extinguish following a series of presentations of the weaker stimulus alone. Additional animals receiving the same number of unpaired presentations of the weak and strong electrical stimuli failed to acquire the tendency to make a motor movement in the presence of the weak stimulus. The weak electrical stimulus coming to evoke a response originally elicited only by a stronger stimulus was explained on the basis of classical conditioning rather than pseudoconditioning or sensitization. © 1971.
Colavita, F. B., & Szeligo, F. (1971). Classical conditioning with brain stimulation at one site serving as both CS and US. Physiology and Behavior, 6(1), 41–44. https://doi.org/10.1016/0031-9384(71)90011-4