title: Transient inactivation of the pigeon hippocampus or the nidopallium caudolaterale during extinction learning impairs extinction retrieval in an appetitive conditioning paradigm.
abstract: The majority of experiments exploring context-dependent extinction learning employ Pavlovian fear conditioning in rodents. Since mechanisms of appetitive and aversive learning are known to differ at the neuronal level, we sought to investigate extinction learning in an appetitive setting. Working with pigeons, we established a within-subject ABA renewal paradigm based on Rescorla (Q J Exp Psychol 61:1793) and combined it with pharmacological interventions during extinction. From the fear conditioning literature, it is known that both prefrontal cortex and the hippocampus are core structures for context-specific extinction learning. Accordingly, we transiently inactivated the nidopallium caudolaterale (NCL, a functional analogue of mammalian prefrontal cortex) and the hippocampus in separate experiments by intracranial infusion of the sodium-channel blocker tetrodotoxin immediately before extinction training. We find that TTX in both structures non-specifically suppresses conditioned responding, as revealed by a reduction of response rate to both the extinguished conditioned stimulus and a control stimulus which remained reinforced throughout the experiment. Furthermore, TTX during extinction training impaired later extinction retrieval assessed under drug-free conditions. This was true when responding to the extinguished stimulus was assessed in the context of extinction but not when tested in the context of acquisition, although both contexts were matched with respect to their history of conditioning. These results indicate that both NCL and hippocampus are involved in extinction learning under appetitive conditions or, more specifically, in the consolidation of extinction memory, and that their contribution to extinction is context-specific.
authors.affiliation: Department of Biopsychology, Faculty of Psychology, Ruhr University Bochum, Bochum, Germany; International Graduate School of Neuroscience, Ruhr University Bochum, Bochum, Germany. Electronic address: daniel.lengersdorf@rub.de.
authors.forename: Daniel
authors.initials: D
authors.lastname: Lengersdorf
authors.affiliation: Department of Biopsychology, Faculty of Psychology, Ruhr University Bochum, Bochum, Germany.
authors.forename: Maik C
authors.initials: MC
authors.lastname: Stüttgen
authors.affiliation: Department of Psychology, Phillips-University Marburg, Marburg, Germany.
authors.forename: Metin
authors.initials: M
authors.lastname: Uengoer
authors.affiliation: Department of Biopsychology, Faculty of Psychology, Ruhr University Bochum, Bochum, Germany.
authors.forename: Onur
authors.initials: O
authors.lastname: Güntürkün
mesh_terms: D000704:Analysis of Variance; D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D001070:Appetitive Behavior / Q000187:drug effects / Q000502:physiology*; D010856:Columbidae; D003214:Conditioning, Classical / Q000187:drug effects / Q000502:physiology*; D005108:Extinction, Psychological / Q000502:physiology*; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D011939:Mental Recall / Q000502:physiology*; D013779:Tetrodotoxin / Q000494:pharmacology
chemical_list: D000779:Anesthetics, Local; D013779:Tetrodotoxin
keywords: Contextual learning; Renewal; Sign tracking; Tetrodotoxin