title: Administration of corticosterone after the first downshift trial enhances consummatory successive negative contrast.
abstract: 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 post-trial injection of corticosterone (3 mg/kg) administered immediately after the first downshift trial. Experiment 2 demonstrated that this facilitatory effect of post-trial corticosterone does not occur when administered 3 hr 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.
authors.affiliation: Laboratorio de Psicología Experimental y Aplicada (PSEA), Instituto de Investigaciones Médicas Lanari, Facultad de Psicología, Universidad de Buenos Aires, Buenos Aires, Argentina.
authors.forename: Mariana
authors.initials: M
authors.lastname: Bentosela
authors.forename: Eliana
authors.initials: E
authors.lastname: Ruetti
authors.forename: Rubén N
authors.initials: RN
authors.lastname: Muzio
authors.forename: Alba E
authors.initials: AE
authors.lastname: Mustaca
authors.forename: Mauricio R
authors.initials: MR
authors.lastname: Papini
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D003216:Conditioning, Operant / Q000187:drug effects / Q000502:physiology; D003259:Consummatory Behavior / Q000187:drug effects* / Q000502:physiology; D003345:Corticosterone / Q000008:administration & dosage*; D007266:Inhibition, Psychological; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013395:Sucrose / Q000494:pharmacology; D013997:Time Factors
chemical_list: D013395:Sucrose; D003345:Corticosterone