Disruption of latent inhibition following systemic administration of parachlorophenylalanine (PCPA)

Abstract

Rats received either 0 or 30 preexposures to a tone which was later used as a CS in a two-way active avoidance task. Tone preexposure resulted in retarded conditioning in normal animals. This latent inhibition effect, however, was not present in rats treated with parachlorophenylalanine. A second experiment used the combined-cue summation test to verify the fact that stimulus preexposure endowed the tone with latent and not conditioned inhibitory properties. The results were discussed in terms of the role of the serotonergic mesolimbic system in tuning out irrelevant stimuli.