title: Differential contribution of dorsal and ventral hippocampus to trace and delay fear conditioning.
abstract: Trace conditioning relies on the maintained representation of a stimulus across a trace interval, and may involve a persistent trace of the conditioned stimulus (CS) and/or a contribution of contextual conditioning. The role of hippocampal structures in these two types of conditioning was studied by means of pretraining lesions and reversible inactivation of the hippocampus in rats. Similar levels of conditioning to a tone CS and to the context were obtained with a trace interval of 30 s. Neurotoxic lesions of the whole hippocampus or reversible muscimol inactivation of the ventral hippocampus impaired both contextual and tone freezing in both trace- and delay-conditioned rats. Dorsal hippocampal injections impaired contextual freezing and trace conditioning, but not delay conditioning. No dissociation between trace and contextual conditioning was observed under any of these conditions. Altogether, these data indicate that the ventral and dorsal parts of the hippocampus compute different aspects of trace conditioning, with the ventral hippocampus being involved in fear and anxiety processes, and the dorsal hippocampus in the temporal and contextual aspects of event representation.
authors.affiliation: Université de Bordeaux, Centre de Neurosciences Intégratives et Cognitives, C.N.R.S. UMR 5228, Talence, France.
authors.forename: Frederic
authors.initials: F
authors.lastname: Esclassan
authors.forename: Etienne
authors.initials: E
authors.lastname: Coutureau
authors.forename: Georges
authors.initials: G
authors.lastname: Di Scala
authors.forename: Alain R
authors.initials: AR
authors.lastname: Marchand
mesh_terms: D000161:Acoustic Stimulation; D000818:Animals; D001007:Anxiety / Q000503:physiopathology / Q000523:psychology; D001362:Avoidance Learning / Q000187:drug effects / Q000502:physiology*; D003213:Conditioning, Psychological / Q000187:drug effects / Q000502:physiology*; D005239:Fear / Q000187:drug effects / Q000502:physiology*; D018755:GABA Agonists / Q000494:pharmacology; D006624:Hippocampus / Q000033:anatomy & histology* / Q000502:physiology*; D008297:Male; D008568:Memory / Q000502:physiology; D009118:Muscimol / Q000494:pharmacology; D009483:Neuropsychological Tests; D009498:Neurotoxins / Q000494:pharmacology; D051381:Rats; D020318:Rats, Long-Evans; D013028:Space Perception / Q000502:physiology
chemical_list: D018755:GABA Agonists; D009498:Neurotoxins; D009118:Muscimol