Administration of Corticosterone After the First Downshift Trial Enhances Consummatory Successive Negative Contrast

MARIANA BENTOSELA, ELIANA RUETTI, RUBÉN N. MUZIO, ALBA E. MUSTACA, MAURICIO R. PAPINI

Behavioral Neuroscience

Año: 2006

Rats given access to a 32% sucrose solution and then downshifted to a 4% solution exhibit less contact with the sipper tube than unshifted controls always given access to 4% solution. This phenomenon, called consummatory successive negative contrast, was facilitated in Experiment 1 by a posttrial injection of corticosterone (3 mg/kg) administered immediately after the first downshift trial. Experiment 2 demonstrated that this facilitatory effect of posttrial corticosterone does not occur when administered 3 h after the first downshift trial. These results support the hypothesis that corticosterone strengthens an aversive emotional component elicited by the surprising downshift in reward magnitude during the initial downshift trial.