title: Corticosterone and decision-making in male Wistar rats: the effect of corticosterone application in the infralimbic and orbitofrontal cortex.
abstract: Corticosteroid hormones, released after stress, are known to influence neuronal activity and produce a wide range of effects upon the brain. They affect cognitive tasks including decision-making. Recently it was shown that systemic injections of corticosterone (CORT) disrupt reward-based decision-making in rats when tested in a rat model of the Iowa Gambling Task (rIGT), i.e., rats do not learn across trial blocks to avoid the long-term disadvantageous option. This effect was associated with a change in neuronal activity in prefrontal brain areas, i.e., the infralimbic (IL), lateral orbitofrontal (lOFC) and insular cortex, as assessed by changes in c-Fos expression. Here, we studied whether injections of CORT directly into the IL and lOFC lead to similar changes in decision-making. As in our earlier study, CORT was injected during the final 3 days of the behavioral paradigm, 25 min prior to behavioral testing. Infusions of vehicle into the IL led to a decreased number of visits to the disadvantageous arm across trial blocks, while infusion with CORT did not. Infusions into the lOFC did not lead to differences in the number of visits to the disadvantageous arm between vehicle treated and CORT treated rats. However, compared to vehicle treated rats of the IL group, performance of vehicle treated rats of the lOFC group was impaired, possibly due to cannulation/infusion-related damage of the lOFC affecting decision-making. Overall, these results show that infusions with CORT into the IL are sufficient to disrupt decision-making performance, pointing to a critical role of the IL in corticosteroid effects on reward-based decision-making. The data do not directly support that the same holds true for infusions into the lOFC.
authors.affiliation: Brain Center Rudolf Magnus, Department of Neuroscience and Pharmacology, University Medical Centre Utrecht Utrecht, Netherlands ; Division Behavioural Neuroscience, Department of Animals in Science and Society, Faculty of Veterinary Medicine, Utrecht University Utrecht, Netherlands.
authors.forename: Susanne
authors.initials: S
authors.lastname: Koot
authors.affiliation: Brain Center Rudolf Magnus, Department of Neuroscience and Pharmacology, University Medical Centre Utrecht Utrecht, Netherlands ; Division Behavioural Neuroscience, Department of Animals in Science and Society, Faculty of Veterinary Medicine, Utrecht University Utrecht, Netherlands.
authors.forename: Magdalini
authors.initials: M
authors.lastname: Koukou
authors.affiliation: Division Behavioural Neuroscience, Department of Animals in Science and Society, Faculty of Veterinary Medicine, Utrecht University Utrecht, Netherlands.
authors.forename: Annemarie
authors.initials: A
authors.lastname: Baars
authors.affiliation: Division Behavioural Neuroscience, Department of Animals in Science and Society, Faculty of Veterinary Medicine, Utrecht University Utrecht, Netherlands.
authors.forename: Peter
authors.initials: P
authors.lastname: Hesseling
authors.affiliation: Division Behavioural Neuroscience, Department of Animals in Science and Society, Faculty of Veterinary Medicine, Utrecht University Utrecht, Netherlands.
authors.forename: José
authors.initials: J
authors.lastname: van 't Klooster
authors.affiliation: Brain Center Rudolf Magnus, Department of Neuroscience and Pharmacology, University Medical Centre Utrecht Utrecht, Netherlands.
authors.forename: Marian
authors.initials: M
authors.lastname: Joëls
authors.affiliation: Brain Center Rudolf Magnus, Department of Neuroscience and Pharmacology, University Medical Centre Utrecht Utrecht, Netherlands ; Department of Organismal Animal Physiology, Radboud University Nijmegen Nijmegen, Netherlands.
authors.forename: Ruud
authors.initials: R
authors.lastname: van den Bos
keywords: Iowa Gambling Task; corticosterone; decision-making; infralimbic/orbitofrontal cortex; rat