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Differential contribution of dorsal and ventral hippocampus to trace and delay fear conditioning
Author(s) -
Esclassan Frederic,
Coutureau Etienne,
Di Scala Georges,
Marchand Alain R.
Publication year - 2009
Publication title -
hippocampus
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.767
H-Index - 155
eISSN - 1098-1063
pISSN - 1050-9631
DOI - 10.1002/hipo.20473
Subject(s) - conditioning , neuroscience , fear conditioning , psychology , classical conditioning , hippocampus , measures of conditioned emotional response , hippocampal formation , engram , muscimol , stimulus (psychology) , neutral stimulus , fear processing in the brain , chemistry , cognitive psychology , amygdala , unconditioned stimulus , stimulus control , agonist , nicotine , biochemistry , statistics , receptor , mathematics
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. © 2008 Wiley‐Liss, Inc.