title: Retrieval induces hippocampal-dependent reconsolidation of spatial memory.
abstract: Nonreinforced retrieval can cause extinction and/or reconsolidation, two processes that affect subsequent retrieval in opposite ways. Using the Morris water maze task we show that, in the rat, repeated nonreinforced expression of spatial memory causes extinction, which is unaffected by inhibition of protein synthesis within the CA1 region of the dorsal hippocampus. However, if the number of nonreinforced retrieval trials is insufficient to induce long-lasting extinction, then a hippocampal protein synthesis-dependent reconsolidation process recovers the original memory. Inhibition of hippocampal protein synthesis after reversal learning sessions impairs retention of the reversed preference and blocks persistence of the original one, suggesting that reversal learning involves reconsolidation rather than extinction of the original memory. Our results suggest the existence of a hippocampal protein synthesis-dependent reconsolidation process that operates to recover or update retrieval-weakened memories from incomplete extinction.
authors.affiliation: Centro de Memória, Instituto de Pesquisas Biomédicas, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brasil.
authors.forename: Janine I
authors.initials: JI
authors.lastname: Rossato
authors.forename: Lia R M
authors.initials: LR
authors.lastname: Bevilaqua
authors.forename: Jorge H
authors.initials: JH
authors.lastname: Medina
authors.forename: Iván
authors.initials: I
authors.lastname: Izquierdo
authors.forename: Martín
authors.initials: M
authors.lastname: Cammarota
mesh_terms: D000818:Animals; D000841:Anisomycin / Q000008:administration & dosage / Q000494:pharmacology; D005108:Extinction, Psychological; D007839:Functional Laterality; D006624:Hippocampus / Q000502:physiology*; D007263:Infusions, Parenteral; D007858:Learning / Q000187:drug effects / Q000502:physiology*; D018782:Maze Learning; D008568:Memory / Q000502:physiology*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D051381:Rats; D012054:Reinforcement, Psychology; D013028:Space Perception / Q000502:physiology*; D013997:Time Factors
chemical_list: D011500:Protein Synthesis Inhibitors; D000841:Anisomycin