title: Encoding and reactivation patterns predictive of successful memory performance are topographically organized along the longitudinal axis of the hippocampus.
abstract: An ongoing debate in human memory research is whether the encoding and the retrieval of memory engage the same part of the hippocampus and the same cells, or whether encoding preferentially involves the anterior part of the hippocampus and retrieval its posterior part. Here, we used a human to rat translational behavioral approach combined to high-resolution molecular imaging to address this issue. We showed that successful memory performance is predicted by encoding and reactivation patterns only in the dorsal part of the rat hippocampus (posterior part in humans), but not in the ventral part (anterior part in humans). Our findings support the view that the encoding and the retrieval processes per se are not segregated along the longitudinal axis of the hippocampus, but that activity predictive of successful memory is and concerns specifically the dorsal part of the hippocampus. In addition, we found evidence that these processes are likely to be mediated by the activation/reactivation of the same cells at this level. Given the translational character of the task, our results suggest that both the encoding and the retrieval processes take place in the same cells of the posterior part of the human hippocampus.
authors.affiliation: Functional Architecture of Memory Unit, Mercator Research Group "Structure Of Memory", Medical Faculty, Ruhr University Bochum, Bochum, 44801, Germany.
authors.forename: Nozomu H
authors.initials: NH
authors.lastname: Nakamura
authors.affiliation: Functional Architecture of Memory Unit, Mercator Research Group "Structure Of Memory", Medical Faculty, Ruhr University Bochum, Bochum, 44801, Germany.
authors.forename: Magdalena M
authors.initials: MM
authors.lastname: Sauvage
mesh_terms: D000818:Animals; D056547:CA1 Region, Hippocampal / Q000166:cytology / Q000502:physiology*; D002352:Carrier Proteins / Q000378:metabolism; D002452:Cell Count; D003598:Cytoskeletal Proteins / Q000378:metabolism; D004192:Discrimination, Psychological / Q000502:physiology; D000072233:Homer Scaffolding Proteins; D017404:In Situ Hybridization, Fluorescence; D007858:Learning / Q000502:physiology*; D008297:Male; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009483:Neuropsychological Tests; D009812:Odorants; D055696:Olfactory Perception / Q000502:physiology*; D046709:Pattern Recognition, Physiological / Q000502:physiology; D010812:Physical Stimulation; D020318:Rats, Long-Evans; D021641:Recognition, Psychology / Q000502:physiology*
chemical_list: D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; D000072233:Homer Scaffolding Proteins; D009419:Nerve Tissue Proteins; C092069:activity regulated cytoskeletal-associated protein
keywords: encoding; hippocampus; memory; reactivation; retrieval