title: Hippocampal c-Fos activation in normal and LPA₁-null mice after two object recognition tasks with different memory demands.
abstract: Normal and LPA₁-null mice, that have well reported hippocampal deficits, were assessed in an episodic-like what-when-where memory task or in a comparable task designed to test memory for familiar objects and locations by discriminating them from novels. Both genotypes performed the novelty recognition task but failed to learn the what-when-where task. However, normal mice showed what-when memory that was impaired in nulls. Each task elicited a different pattern of c-Fos expression. In normal mice, the what-when-where task induced more hippocampal c-Fos activation in the CA1 area than the novelty-based task, correlating with the what-when memory. LPA₁-null mice displayed a basal c-Fos hyperactivity in the hippocampus and in the medial prefrontal cortex, which was regulated differently by the two behavioural tasks employed. Both tasks were matched in exploratory behaviour and c-Fos activation in stress-related brain areas for both genotypes. This study shows that the what-when-where memory task differs from a comparable novelty-based task in both the learning demands and the neuronal correlates. Moreover, results also stress the role of the LPA₁ receptor in hippocampal functioning.
authors.affiliation: Departamento de Psicobiología y Metodología de las CC, Universidad de Málaga, Campus de Teatinos, 29071 Málaga, Spain.
authors.forename: Estela
authors.initials: E
authors.lastname: Castilla-Ortega
authors.forename: Carmen
authors.initials: C
authors.lastname: Pedraza
authors.forename: Jerold
authors.initials: J
authors.lastname: Chun
authors.forename: Fernando Rodríguez
authors.initials: FR
authors.lastname: de Fonseca
authors.forename: Guillermo
authors.initials: G
authors.lastname: Estivill-Torrús
authors.forename: Luis J
authors.initials: LJ
authors.lastname: Santín
mesh_terms: D000818:Animals; D005106:Exploratory Behavior / Q000502:physiology; D006624:Hippocampus / Q000378:metabolism*; D008297:Male; D061212:Memory, Episodic; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D049368:Receptors, Lysophosphatidic Acid / Q000235:genetics / Q000378:metabolism*; D021641:Recognition, Psychology / Q000502:physiology*; D014018:Tissue Distribution
chemical_list: D016760:Proto-Oncogene Proteins c-fos; D049368:Receptors, Lysophosphatidic Acid