Enhancement of conditioned inhibition via an extinction treatment

Abstract

Rats were used in a conditioned-suppression paradigm to determine whether an extinction treatment would enhance a moderately developed conditioned inhibitor (CS-). To dissipate unconditioned suppression to the training stimuli, the subjects were first habituated to the stimuli and then given Pavlovian conditioned-inhibition (CI) training involving reinforced presentations of a clicker and nonreinforced compound presentations of that stimulus and the intended CS-, either a light or a tone. Thereafter, experimental subjects received presentations of their CS- by itself, whereas controls received no further training. Following the occurrence and loss of conditioned suppression to the CS- in the extinction phase, summation and retardation tests showed enhanced CI for the experimental subjects relative to both the controls and their own earlier levels of inhibitory performance. In fact, the enhanced inhibition for the experimental subjects approximated that shown by a comparison group for which the CS- had been strongly developed as an inhibitor. These findings suggest that an excitatory representation is associated with the CS- early in CI training, and that subsequent presentations of the CS- by itself strengthen its inhibitory effect by allowing it to be nonreinforced in the presence of that representation. © 1987 Psychonomic Society, Inc.